/*
 *      IPv6 Address [auto]configuration
 *      Linux INET6 implementation
 *
 *      Authors:
 *      Pedro Roque             <roque@di.fc.ul.pt>
 *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

/*
 *      Changes:
 *
 *      Janos Farkas                    :       delete timer on ifdown
 *      <chexum@bankinf.banki.hu>
 *      Andi Kleen                      :       kill double kfree on module
 *                                              unload.
 *      Maciej W. Rozycki               :       FDDI support
 *      sekiya@USAGI                    :       Don't send too many RS
 *                                              packets.
 *      yoshfuji@USAGI                  :       Fixed interval between DAD
 *                                              packets.
 *      YOSHIFUJI Hideaki @USAGI        :       improved accuracy of
 *                                              address validation timer.
 *      YOSHIFUJI Hideaki @USAGI        :       Privacy Extensions (RFC3041)
 *                                              support.
 *      Yuji SEKIYA @USAGI              :       Don't assign a same IPv6
 *                                              address on a same interface.
 *      YOSHIFUJI Hideaki @USAGI        :       ARCnet support
 *      YOSHIFUJI Hideaki @USAGI        :       convert /proc/net/if_inet6 to
 *                                              seq_file.
 *      YOSHIFUJI Hideaki @USAGI        :       improved source address
 *                                              selection; consider scope,
 *                                              status etc.
 */

#define pr_fmt(fmt) "IPv6: " fmt

#include <linux/errno.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/in6.h>
#include <linux/netdevice.h>
#include <linux/if_addr.h>
#include <linux/if_arp.h>
#include <linux/if_arcnet.h>
#include <linux/if_infiniband.h>
#include <linux/route.h>
#include <linux/inetdevice.h>
#include <linux/init.h>
#include <linux/slab.h>
#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
#endif
#include <linux/capability.h>
#include <linux/delay.h>
#include <linux/notifier.h>
#include <linux/string.h>
#include <linux/hash.h>

#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/snmp.h>

#include <net/af_ieee802154.h>
#include <net/firewire.h>
#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/ndisc.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>
#include <net/tcp.h>
#include <net/ip.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <linux/if_tunnel.h>
#include <linux/rtnetlink.h>
#include <linux/netconf.h>

#ifdef CONFIG_IPV6_PRIVACY
#include <linux/random.h>
#endif

#include <linux/uaccess.h>
#include <asm/unaligned.h>

#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/export.h>

/* Set to 3 to get tracing... */
#define ACONF_DEBUG 2

#if ACONF_DEBUG >= 3
#define ADBG(x) printk x
#else
#define ADBG(x)
#endif

#define INFINITY_LIFE_TIME      0xFFFFFFFF

static inline u32 cstamp_delta(unsigned long cstamp)
{
        return (cstamp - INITIAL_JIFFIES) * 100UL / HZ;
}

#ifdef CONFIG_SYSCTL
static void addrconf_sysctl_register(struct inet6_dev *idev);
static void addrconf_sysctl_unregister(struct inet6_dev *idev);
#else
static inline void addrconf_sysctl_register(struct inet6_dev *idev)
{
}

static inline void addrconf_sysctl_unregister(struct inet6_dev *idev)
{
}
#endif

#ifdef CONFIG_IPV6_PRIVACY
static void __ipv6_regen_rndid(struct inet6_dev *idev);
static void __ipv6_try_regen_rndid(struct inet6_dev *idev, struct in6_addr *tmpaddr);
static void ipv6_regen_rndid(unsigned long data);
#endif

static int ipv6_generate_eui64(u8 *eui, struct net_device *dev);
static int ipv6_count_addresses(struct inet6_dev *idev);

/*
 *      Configured unicast address hash table
 */
static struct hlist_head inet6_addr_lst[IN6_ADDR_HSIZE];
static DEFINE_SPINLOCK(addrconf_hash_lock);

static void addrconf_verify(unsigned long);

static DEFINE_TIMER(addr_chk_timer, addrconf_verify, 0, 0);
static DEFINE_SPINLOCK(addrconf_verify_lock);

static void addrconf_join_anycast(struct inet6_ifaddr *ifp);
static void addrconf_leave_anycast(struct inet6_ifaddr *ifp);

static void addrconf_type_change(struct net_device *dev,
                                 unsigned long event);
static int addrconf_ifdown(struct net_device *dev, int how);

static struct rt6_info *addrconf_get_prefix_route(const struct in6_addr *pfx,
                                                  int plen,
                                                  const struct net_device *dev,
                                                  u32 flags, u32 noflags);

static void addrconf_dad_start(struct inet6_ifaddr *ifp);
static void addrconf_dad_timer(unsigned long data);
static void addrconf_dad_completed(struct inet6_ifaddr *ifp);
static void addrconf_dad_run(struct inet6_dev *idev);
static void addrconf_rs_timer(unsigned long data);
static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifa);
static void ipv6_ifa_notify(int event, struct inet6_ifaddr *ifa);

static void inet6_prefix_notify(int event, struct inet6_dev *idev,
                                struct prefix_info *pinfo);
static bool ipv6_chk_same_addr(struct net *net, const struct in6_addr *addr,
                               struct net_device *dev);

static struct ipv6_devconf ipv6_devconf __read_mostly = {
        .forwarding             = 0,
        .hop_limit              = IPV6_DEFAULT_HOPLIMIT,
        .mtu6                   = IPV6_MIN_MTU,
        .accept_ra              = 1,
        .accept_redirects       = 1,
        .autoconf               = 1,
        .force_mld_version      = 0,
        .dad_transmits          = 1,
        .rtr_solicits           = MAX_RTR_SOLICITATIONS,
        .rtr_solicit_interval   = RTR_SOLICITATION_INTERVAL,
        .rtr_solicit_delay      = MAX_RTR_SOLICITATION_DELAY,
#ifdef CONFIG_IPV6_PRIVACY
        .use_tempaddr           = 0,
        .temp_valid_lft         = TEMP_VALID_LIFETIME,
        .temp_prefered_lft      = TEMP_PREFERRED_LIFETIME,
        .regen_max_retry        = REGEN_MAX_RETRY,
        .max_desync_factor      = MAX_DESYNC_FACTOR,
#endif
        .max_addresses          = IPV6_MAX_ADDRESSES,
        .accept_ra_defrtr       = 1,
        .accept_ra_pinfo        = 1,
#ifdef CONFIG_IPV6_ROUTER_PREF
        .accept_ra_rtr_pref     = 1,
        .rtr_probe_interval     = 60 * HZ,
#ifdef CONFIG_IPV6_ROUTE_INFO
        .accept_ra_rt_info_max_plen = 0,
#endif
#endif
        .proxy_ndp              = 0,
        .accept_source_route    = 0,    /* we do not accept RH0 by default. */
        .disable_ipv6           = 0,
        .accept_dad             = 1,
};

static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
        .forwarding             = 0,
        .hop_limit              = IPV6_DEFAULT_HOPLIMIT,
        .mtu6                   = IPV6_MIN_MTU,
        .accept_ra              = 1,
        .accept_redirects       = 1,
        .autoconf               = 1,
        .dad_transmits          = 1,
        .rtr_solicits           = MAX_RTR_SOLICITATIONS,
        .rtr_solicit_interval   = RTR_SOLICITATION_INTERVAL,
        .rtr_solicit_delay      = MAX_RTR_SOLICITATION_DELAY,
#ifdef CONFIG_IPV6_PRIVACY
        .use_tempaddr           = 0,
        .temp_valid_lft         = TEMP_VALID_LIFETIME,
        .temp_prefered_lft      = TEMP_PREFERRED_LIFETIME,
        .regen_max_retry        = REGEN_MAX_RETRY,
        .max_desync_factor      = MAX_DESYNC_FACTOR,
#endif
        .max_addresses          = IPV6_MAX_ADDRESSES,
        .accept_ra_defrtr       = 1,
        .accept_ra_pinfo        = 1,
#ifdef CONFIG_IPV6_ROUTER_PREF
        .accept_ra_rtr_pref     = 1,
        .rtr_probe_interval     = 60 * HZ,
#ifdef CONFIG_IPV6_ROUTE_INFO
        .accept_ra_rt_info_max_plen = 0,
#endif
#endif
        .proxy_ndp              = 0,
        .accept_source_route    = 0,    /* we do not accept RH0 by default. */
        .disable_ipv6           = 0,
        .accept_dad             = 1,
};

/* IPv6 Wildcard Address and Loopback Address defined by RFC2553 */
const struct in6_addr in6addr_any = IN6ADDR_ANY_INIT;
const struct in6_addr in6addr_loopback = IN6ADDR_LOOPBACK_INIT;
const struct in6_addr in6addr_linklocal_allnodes = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
const struct in6_addr in6addr_linklocal_allrouters = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
const struct in6_addr in6addr_interfacelocal_allnodes = IN6ADDR_INTERFACELOCAL_ALLNODES_INIT;
const struct in6_addr in6addr_interfacelocal_allrouters = IN6ADDR_INTERFACELOCAL_ALLROUTERS_INIT;
const struct in6_addr in6addr_sitelocal_allrouters = IN6ADDR_SITELOCAL_ALLROUTERS_INIT;

/* Check if a valid qdisc is available */
static inline bool addrconf_qdisc_ok(const struct net_device *dev)
{
        return !qdisc_tx_is_noop(dev);
}

static void addrconf_del_timer(struct inet6_ifaddr *ifp)
{
        if (del_timer(&ifp->timer))
                __in6_ifa_put(ifp);
}

enum addrconf_timer_t {
        AC_NONE,
        AC_DAD,
        AC_RS,
};

static void addrconf_mod_timer(struct inet6_ifaddr *ifp,
                               enum addrconf_timer_t what,
                               unsigned long when)
{
        if (!del_timer(&ifp->timer))
                in6_ifa_hold(ifp);

        switch (what) {
        case AC_DAD:
                ifp->timer.function = addrconf_dad_timer;
                break;
        case AC_RS:
                ifp->timer.function = addrconf_rs_timer;
                break;
        default:
                break;
        }
        ifp->timer.expires = jiffies + when;
        add_timer(&ifp->timer);
}

static int snmp6_alloc_dev(struct inet6_dev *idev)
{
        if (snmp_mib_init((void __percpu **)idev->stats.ipv6,
                          sizeof(struct ipstats_mib),
                          __alignof__(struct ipstats_mib)) < 0)
                goto err_ip;
        idev->stats.icmpv6dev = kzalloc(sizeof(struct icmpv6_mib_device),
                                        GFP_KERNEL);
        if (!idev->stats.icmpv6dev)
                goto err_icmp;
        idev->stats.icmpv6msgdev = kzalloc(sizeof(struct icmpv6msg_mib_device),
                                           GFP_KERNEL);
        if (!idev->stats.icmpv6msgdev)
                goto err_icmpmsg;

        return 0;

err_icmpmsg:
        kfree(idev->stats.icmpv6dev);
err_icmp:
        snmp_mib_free((void __percpu **)idev->stats.ipv6);
err_ip:
        return -ENOMEM;
}

static void snmp6_free_dev(struct inet6_dev *idev)
{
        kfree(idev->stats.icmpv6msgdev);
        kfree(idev->stats.icmpv6dev);
        snmp_mib_free((void __percpu **)idev->stats.ipv6);
}

/* Nobody refers to this device, we may destroy it. */

void in6_dev_finish_destroy(struct inet6_dev *idev)
{
        struct net_device *dev = idev->dev;

        WARN_ON(!list_empty(&idev->addr_list));
        WARN_ON(idev->mc_list != NULL);

#ifdef NET_REFCNT_DEBUG
        pr_debug("%s: %s\n", __func__, dev ? dev->name : "NIL");
#endif
        dev_put(dev);
        if (!idev->dead) {
                pr_warn("Freeing alive inet6 device %p\n", idev);
                return;
        }
        snmp6_free_dev(idev);
        kfree_rcu(idev, rcu);
}
EXPORT_SYMBOL(in6_dev_finish_destroy);

static struct inet6_dev *ipv6_add_dev(struct net_device *dev)
{
        struct inet6_dev *ndev;

        ASSERT_RTNL();

        if (dev->mtu < IPV6_MIN_MTU)
                return NULL;

        ndev = kzalloc(sizeof(struct inet6_dev), GFP_KERNEL);

        if (ndev == NULL)
                return NULL;

        rwlock_init(&ndev->lock);
        ndev->dev = dev;
        INIT_LIST_HEAD(&ndev->addr_list);

        memcpy(&ndev->cnf, dev_net(dev)->ipv6.devconf_dflt, sizeof(ndev->cnf));
        ndev->cnf.mtu6 = dev->mtu;
        ndev->cnf.sysctl = NULL;
        ndev->nd_parms = neigh_parms_alloc(dev, &nd_tbl);
        if (ndev->nd_parms == NULL) {
                kfree(ndev);
                return NULL;
        }
        if (ndev->cnf.forwarding)
                dev_disable_lro(dev);
        /* We refer to the device */
        dev_hold(dev);

        if (snmp6_alloc_dev(ndev) < 0) {
                ADBG((KERN_WARNING
                        "%s: cannot allocate memory for statistics; dev=%s.\n",
                        __func__, dev->name));
                neigh_parms_release(&nd_tbl, ndev->nd_parms);
                dev_put(dev);
                kfree(ndev);
                return NULL;
        }

        if (snmp6_register_dev(ndev) < 0) {
                ADBG((KERN_WARNING
                        "%s: cannot create /proc/net/dev_snmp6/%s\n",
                        __func__, dev->name));
                neigh_parms_release(&nd_tbl, ndev->nd_parms);
                ndev->dead = 1;
                in6_dev_finish_destroy(ndev);
                return NULL;
        }

        /* One reference from device.  We must do this before
         * we invoke __ipv6_regen_rndid().
         */
        in6_dev_hold(ndev);

        if (dev->flags & (IFF_NOARP | IFF_LOOPBACK))
                ndev->cnf.accept_dad = -1;

#if IS_ENABLED(CONFIG_IPV6_SIT)
        if (dev->type == ARPHRD_SIT && (dev->priv_flags & IFF_ISATAP)) {
                pr_info("%s: Disabled Multicast RS\n", dev->name);
                ndev->cnf.rtr_solicits = 0;
        }
#endif

#ifdef CONFIG_IPV6_PRIVACY
        INIT_LIST_HEAD(&ndev->tempaddr_list);
        setup_timer(&ndev->regen_timer, ipv6_regen_rndid, (unsigned long)ndev);
        if ((dev->flags&IFF_LOOPBACK) ||
            dev->type == ARPHRD_TUNNEL ||
            dev->type == ARPHRD_TUNNEL6 ||
            dev->type == ARPHRD_SIT ||
            dev->type == ARPHRD_NONE) {
                ndev->cnf.use_tempaddr = -1;
        } else {
                in6_dev_hold(ndev);
                ipv6_regen_rndid((unsigned long) ndev);
        }
#endif
        ndev->token = in6addr_any;

        if (netif_running(dev) && addrconf_qdisc_ok(dev))
                ndev->if_flags |= IF_READY;

        ipv6_mc_init_dev(ndev);
        ndev->tstamp = jiffies;
        addrconf_sysctl_register(ndev);
        /* protected by rtnl_lock */
        rcu_assign_pointer(dev->ip6_ptr, ndev);

        /* Join interface-local all-node multicast group */
        ipv6_dev_mc_inc(dev, &in6addr_interfacelocal_allnodes);

        /* Join all-node multicast group */
        ipv6_dev_mc_inc(dev, &in6addr_linklocal_allnodes);

        /* Join all-router multicast group if forwarding is set */
        if (ndev->cnf.forwarding && (dev->flags & IFF_MULTICAST))
                ipv6_dev_mc_inc(dev, &in6addr_linklocal_allrouters);

        return ndev;
}

static struct inet6_dev *ipv6_find_idev(struct net_device *dev)
{
        struct inet6_dev *idev;

        ASSERT_RTNL();

        idev = __in6_dev_get(dev);
        if (!idev) {
                idev = ipv6_add_dev(dev);
                if (!idev)
                        return NULL;
        }

        if (dev->flags&IFF_UP)
                ipv6_mc_up(idev);
        return idev;
}

static int inet6_netconf_msgsize_devconf(int type)
{
        int size =  NLMSG_ALIGN(sizeof(struct netconfmsg))
                    + nla_total_size(4);        /* NETCONFA_IFINDEX */

        /* type -1 is used for ALL */
        if (type == -1 || type == NETCONFA_FORWARDING)
                size += nla_total_size(4);
#ifdef CONFIG_IPV6_MROUTE
        if (type == -1 || type == NETCONFA_MC_FORWARDING)
                size += nla_total_size(4);
#endif

        return size;
}

static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
                                      struct ipv6_devconf *devconf, u32 portid,
                                      u32 seq, int event, unsigned int flags,
                                      int type)
{
        struct nlmsghdr  *nlh;
        struct netconfmsg *ncm;

        nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct netconfmsg),
                        flags);
        if (nlh == NULL)
                return -EMSGSIZE;

        ncm = nlmsg_data(nlh);
        ncm->ncm_family = AF_INET6;

        if (nla_put_s32(skb, NETCONFA_IFINDEX, ifindex) < 0)
                goto nla_put_failure;

        /* type -1 is used for ALL */
        if ((type == -1 || type == NETCONFA_FORWARDING) &&
            nla_put_s32(skb, NETCONFA_FORWARDING, devconf->forwarding) < 0)
                goto nla_put_failure;
#ifdef CONFIG_IPV6_MROUTE
        if ((type == -1 || type == NETCONFA_MC_FORWARDING) &&
            nla_put_s32(skb, NETCONFA_MC_FORWARDING,
                        devconf->mc_forwarding) < 0)
                goto nla_put_failure;
#endif
        return nlmsg_end(skb, nlh);

nla_put_failure:
        nlmsg_cancel(skb, nlh);
        return -EMSGSIZE;
}

void inet6_netconf_notify_devconf(struct net *net, int type, int ifindex,
                                  struct ipv6_devconf *devconf)
{
        struct sk_buff *skb;
        int err = -ENOBUFS;

        skb = nlmsg_new(inet6_netconf_msgsize_devconf(type), GFP_ATOMIC);
        if (skb == NULL)
                goto errout;

        err = inet6_netconf_fill_devconf(skb, ifindex, devconf, 0, 0,
                                         RTM_NEWNETCONF, 0, type);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in inet6_netconf_msgsize_devconf() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout;
        }
        rtnl_notify(skb, net, 0, RTNLGRP_IPV6_NETCONF, NULL, GFP_ATOMIC);
        return;
errout:
        rtnl_set_sk_err(net, RTNLGRP_IPV6_NETCONF, err);
}

static const struct nla_policy devconf_ipv6_policy[NETCONFA_MAX+1] = {
        [NETCONFA_IFINDEX]      = { .len = sizeof(int) },
        [NETCONFA_FORWARDING]   = { .len = sizeof(int) },
};

static int inet6_netconf_get_devconf(struct sk_buff *in_skb,
                                     struct nlmsghdr *nlh)
{
        struct net *net = sock_net(in_skb->sk);
        struct nlattr *tb[NETCONFA_MAX+1];
        struct netconfmsg *ncm;
        struct sk_buff *skb;
        struct ipv6_devconf *devconf;
        struct inet6_dev *in6_dev;
        struct net_device *dev;
        int ifindex;
        int err;

        err = nlmsg_parse(nlh, sizeof(*ncm), tb, NETCONFA_MAX,
                          devconf_ipv6_policy);
        if (err < 0)
                goto errout;

        err = EINVAL;
        if (!tb[NETCONFA_IFINDEX])
                goto errout;

        ifindex = nla_get_s32(tb[NETCONFA_IFINDEX]);
        switch (ifindex) {
        case NETCONFA_IFINDEX_ALL:
                devconf = net->ipv6.devconf_all;
                break;
        case NETCONFA_IFINDEX_DEFAULT:
                devconf = net->ipv6.devconf_dflt;
                break;
        default:
                dev = __dev_get_by_index(net, ifindex);
                if (dev == NULL)
                        goto errout;
                in6_dev = __in6_dev_get(dev);
                if (in6_dev == NULL)
                        goto errout;
                devconf = &in6_dev->cnf;
                break;
        }

        err = -ENOBUFS;
        skb = nlmsg_new(inet6_netconf_msgsize_devconf(-1), GFP_ATOMIC);
        if (skb == NULL)
                goto errout;

        err = inet6_netconf_fill_devconf(skb, ifindex, devconf,
                                         NETLINK_CB(in_skb).portid,
                                         nlh->nlmsg_seq, RTM_NEWNETCONF, 0,
                                         -1);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in inet6_netconf_msgsize_devconf() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout;
        }
        err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
errout:
        return err;
}

static int inet6_netconf_dump_devconf(struct sk_buff *skb,
                                      struct netlink_callback *cb)
{
        struct net *net = sock_net(skb->sk);
        int h, s_h;
        int idx, s_idx;
        struct net_device *dev;
        struct inet6_dev *idev;
        struct hlist_head *head;

        s_h = cb->args[0];
        s_idx = idx = cb->args[1];

        for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
                idx = 0;
                head = &net->dev_index_head[h];
                rcu_read_lock();
                cb->seq = atomic_read(&net->ipv6.dev_addr_genid) ^
                          net->dev_base_seq;
                hlist_for_each_entry_rcu(dev, head, index_hlist) {
                        if (idx < s_idx)
                                goto cont;
                        idev = __in6_dev_get(dev);
                        if (!idev)
                                goto cont;

                        if (inet6_netconf_fill_devconf(skb, dev->ifindex,
                                                       &idev->cnf,
                                                       NETLINK_CB(cb->skb).portid,
                                                       cb->nlh->nlmsg_seq,
                                                       RTM_NEWNETCONF,
                                                       NLM_F_MULTI,
                                                       -1) <= 0) {
                                rcu_read_unlock();
                                goto done;
                        }
                        nl_dump_check_consistent(cb, nlmsg_hdr(skb));
cont:
                        idx++;
                }
                rcu_read_unlock();
        }
        if (h == NETDEV_HASHENTRIES) {
                if (inet6_netconf_fill_devconf(skb, NETCONFA_IFINDEX_ALL,
                                               net->ipv6.devconf_all,
                                               NETLINK_CB(cb->skb).portid,
                                               cb->nlh->nlmsg_seq,
                                               RTM_NEWNETCONF, NLM_F_MULTI,
                                               -1) <= 0)
                        goto done;
                else
                        h++;
        }
        if (h == NETDEV_HASHENTRIES + 1) {
                if (inet6_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT,
                                               net->ipv6.devconf_dflt,
                                               NETLINK_CB(cb->skb).portid,
                                               cb->nlh->nlmsg_seq,
                                               RTM_NEWNETCONF, NLM_F_MULTI,
                                               -1) <= 0)
                        goto done;
                else
                        h++;
        }
done:
        cb->args[0] = h;
        cb->args[1] = idx;

        return skb->len;
}

#ifdef CONFIG_SYSCTL
static void dev_forward_change(struct inet6_dev *idev)
{
        struct net_device *dev;
        struct inet6_ifaddr *ifa;

        if (!idev)
                return;
        dev = idev->dev;
        if (idev->cnf.forwarding)
                dev_disable_lro(dev);
        if (dev->flags & IFF_MULTICAST) {
                if (idev->cnf.forwarding) {
                        ipv6_dev_mc_inc(dev, &in6addr_linklocal_allrouters);
                        ipv6_dev_mc_inc(dev, &in6addr_interfacelocal_allrouters);
                        ipv6_dev_mc_inc(dev, &in6addr_sitelocal_allrouters);
                } else {
                        ipv6_dev_mc_dec(dev, &in6addr_linklocal_allrouters);
                        ipv6_dev_mc_dec(dev, &in6addr_interfacelocal_allrouters);
                        ipv6_dev_mc_dec(dev, &in6addr_sitelocal_allrouters);
                }
        }

        list_for_each_entry(ifa, &idev->addr_list, if_list) {
                if (ifa->flags&IFA_F_TENTATIVE)
                        continue;
                if (idev->cnf.forwarding)
                        addrconf_join_anycast(ifa);
                else
                        addrconf_leave_anycast(ifa);
        }
        inet6_netconf_notify_devconf(dev_net(dev), NETCONFA_FORWARDING,
                                     dev->ifindex, &idev->cnf);
}


static void addrconf_forward_change(struct net *net, __s32 newf)
{
        struct net_device *dev;
        struct inet6_dev *idev;

        for_each_netdev(net, dev) {
                idev = __in6_dev_get(dev);
                if (idev) {
                        int changed = (!idev->cnf.forwarding) ^ (!newf);
                        idev->cnf.forwarding = newf;
                        if (changed)
                                dev_forward_change(idev);
                }
        }
}

static int addrconf_fixup_forwarding(struct ctl_table *table, int *p, int newf)
{
        struct net *net;
        int old;

        if (!rtnl_trylock())
                return restart_syscall();

        net = (struct net *)table->extra2;
        old = *p;
        *p = newf;

        if (p == &net->ipv6.devconf_dflt->forwarding) {
                if ((!newf) ^ (!old))
                        inet6_netconf_notify_devconf(net, NETCONFA_FORWARDING,
                                                     NETCONFA_IFINDEX_DEFAULT,
                                                     net->ipv6.devconf_dflt);
                rtnl_unlock();
                return 0;
        }

        if (p == &net->ipv6.devconf_all->forwarding) {
                net->ipv6.devconf_dflt->forwarding = newf;
                addrconf_forward_change(net, newf);
                if ((!newf) ^ (!old))
                        inet6_netconf_notify_devconf(net, NETCONFA_FORWARDING,
                                                     NETCONFA_IFINDEX_ALL,
                                                     net->ipv6.devconf_all);
        } else if ((!newf) ^ (!old))
                dev_forward_change((struct inet6_dev *)table->extra1);
        rtnl_unlock();

        if (newf)
                rt6_purge_dflt_routers(net);
        return 1;
}
#endif

/* Nobody refers to this ifaddr, destroy it */
void inet6_ifa_finish_destroy(struct inet6_ifaddr *ifp)
{
        WARN_ON(!hlist_unhashed(&ifp->addr_lst));

#ifdef NET_REFCNT_DEBUG
        pr_debug("%s\n", __func__);
#endif

        in6_dev_put(ifp->idev);

        if (del_timer(&ifp->timer))
                pr_notice("Timer is still running, when freeing ifa=%p\n", ifp);

        if (ifp->state != INET6_IFADDR_STATE_DEAD) {
                pr_warn("Freeing alive inet6 address %p\n", ifp);
                return;
        }
        ip6_rt_put(ifp->rt);

        kfree_rcu(ifp, rcu);
}

static void
ipv6_link_dev_addr(struct inet6_dev *idev, struct inet6_ifaddr *ifp)
{
        struct list_head *p;
        int ifp_scope = ipv6_addr_src_scope(&ifp->addr);

        /*
         * Each device address list is sorted in order of scope -
         * global before linklocal.
         */
        list_for_each(p, &idev->addr_list) {
                struct inet6_ifaddr *ifa
                        = list_entry(p, struct inet6_ifaddr, if_list);
                if (ifp_scope >= ipv6_addr_src_scope(&ifa->addr))
                        break;
        }

        list_add_tail(&ifp->if_list, p);
}

static u32 inet6_addr_hash(const struct in6_addr *addr)
{
        return hash_32(ipv6_addr_hash(addr), IN6_ADDR_HSIZE_SHIFT);
}

/* On success it returns ifp with increased reference count */

static struct inet6_ifaddr *
ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr, int pfxlen,
              int scope, u32 flags)
{
        struct inet6_ifaddr *ifa = NULL;
        struct rt6_info *rt;
        unsigned int hash;
        int err = 0;
        int addr_type = ipv6_addr_type(addr);

        if (addr_type == IPV6_ADDR_ANY ||
            addr_type & IPV6_ADDR_MULTICAST ||
            (!(idev->dev->flags & IFF_LOOPBACK) &&
             addr_type & IPV6_ADDR_LOOPBACK))
                return ERR_PTR(-EADDRNOTAVAIL);

        rcu_read_lock_bh();
        if (idev->dead) {
                err = -ENODEV;                  /*XXX*/
                goto out2;
        }

        if (idev->cnf.disable_ipv6) {
                err = -EACCES;
                goto out2;
        }

        spin_lock(&addrconf_hash_lock);

        /* Ignore adding duplicate addresses on an interface */
        if (ipv6_chk_same_addr(dev_net(idev->dev), addr, idev->dev)) {
                ADBG(("ipv6_add_addr: already assigned\n"));
                err = -EEXIST;
                goto out;
        }

        ifa = kzalloc(sizeof(struct inet6_ifaddr), GFP_ATOMIC);

        if (ifa == NULL) {
                ADBG(("ipv6_add_addr: malloc failed\n"));
                err = -ENOBUFS;
                goto out;
        }

        rt = addrconf_dst_alloc(idev, addr, false);
        if (IS_ERR(rt)) {
                err = PTR_ERR(rt);
                goto out;
        }

        ifa->addr = *addr;

        spin_lock_init(&ifa->lock);
        spin_lock_init(&ifa->state_lock);
        init_timer(&ifa->timer);
        INIT_HLIST_NODE(&ifa->addr_lst);
        ifa->timer.data = (unsigned long) ifa;
        ifa->scope = scope;
        ifa->prefix_len = pfxlen;
        ifa->flags = flags | IFA_F_TENTATIVE;
        ifa->cstamp = ifa->tstamp = jiffies;
        ifa->tokenized = false;

        ifa->rt = rt;

        ifa->idev = idev;
        in6_dev_hold(idev);
        /* For caller */
        in6_ifa_hold(ifa);

        /* Add to big hash table */
        hash = inet6_addr_hash(addr);

        hlist_add_head_rcu(&ifa->addr_lst, &inet6_addr_lst[hash]);
        spin_unlock(&addrconf_hash_lock);

        write_lock(&idev->lock);
        /* Add to inet6_dev unicast addr list. */
        ipv6_link_dev_addr(idev, ifa);

#ifdef CONFIG_IPV6_PRIVACY
        if (ifa->flags&IFA_F_TEMPORARY) {
                list_add(&ifa->tmp_list, &idev->tempaddr_list);
                in6_ifa_hold(ifa);
        }
#endif

        in6_ifa_hold(ifa);
        write_unlock(&idev->lock);
out2:
        rcu_read_unlock_bh();

        if (likely(err == 0))
                inet6addr_notifier_call_chain(NETDEV_UP, ifa);
        else {
                kfree(ifa);
                ifa = ERR_PTR(err);
        }

        return ifa;
out:
        spin_unlock(&addrconf_hash_lock);
        goto out2;
}

/* This function wants to get referenced ifp and releases it before return */

static void ipv6_del_addr(struct inet6_ifaddr *ifp)
{
        struct inet6_ifaddr *ifa, *ifn;
        struct inet6_dev *idev = ifp->idev;
        int state;
        int deleted = 0, onlink = 0;
        unsigned long expires = jiffies;

        spin_lock_bh(&ifp->state_lock);
        state = ifp->state;
        ifp->state = INET6_IFADDR_STATE_DEAD;
        spin_unlock_bh(&ifp->state_lock);

        if (state == INET6_IFADDR_STATE_DEAD)
                goto out;

        spin_lock_bh(&addrconf_hash_lock);
        hlist_del_init_rcu(&ifp->addr_lst);
        spin_unlock_bh(&addrconf_hash_lock);

        write_lock_bh(&idev->lock);
#ifdef CONFIG_IPV6_PRIVACY
        if (ifp->flags&IFA_F_TEMPORARY) {
                list_del(&ifp->tmp_list);
                if (ifp->ifpub) {
                        in6_ifa_put(ifp->ifpub);
                        ifp->ifpub = NULL;
                }
                __in6_ifa_put(ifp);
        }
#endif

        list_for_each_entry_safe(ifa, ifn, &idev->addr_list, if_list) {
                if (ifa == ifp) {
                        list_del_init(&ifp->if_list);
                        __in6_ifa_put(ifp);

                        if (!(ifp->flags & IFA_F_PERMANENT) || onlink > 0)
                                break;
                        deleted = 1;
                        continue;
                } else if (ifp->flags & IFA_F_PERMANENT) {
                        if (ipv6_prefix_equal(&ifa->addr, &ifp->addr,
                                              ifp->prefix_len)) {
                                if (ifa->flags & IFA_F_PERMANENT) {
                                        onlink = 1;
                                        if (deleted)
                                                break;
                                } else {
                                        unsigned long lifetime;

                                        if (!onlink)
                                                onlink = -1;

                                        spin_lock(&ifa->lock);

                                        lifetime = addrconf_timeout_fixup(ifa->valid_lft, HZ);
                                        /*
                                         * Note: Because this address is
                                         * not permanent, lifetime <
                                         * LONG_MAX / HZ here.
                                         */
                                        if (time_before(expires,
                                                        ifa->tstamp + lifetime * HZ))
                                                expires = ifa->tstamp + lifetime * HZ;
                                        spin_unlock(&ifa->lock);
                                }
                        }
                }
        }
        write_unlock_bh(&idev->lock);

        addrconf_del_timer(ifp);

        ipv6_ifa_notify(RTM_DELADDR, ifp);

        inet6addr_notifier_call_chain(NETDEV_DOWN, ifp);

        /*
         * Purge or update corresponding prefix
         *
         * 1) we don't purge prefix here if address was not permanent.
         *    prefix is managed by its own lifetime.
         * 2) if there're no addresses, delete prefix.
         * 3) if there're still other permanent address(es),
         *    corresponding prefix is still permanent.
         * 4) otherwise, update prefix lifetime to the
         *    longest valid lifetime among the corresponding
         *    addresses on the device.
         *    Note: subsequent RA will update lifetime.
         *
         * --yoshfuji
         */
        if ((ifp->flags & IFA_F_PERMANENT) && onlink < 1) {
                struct in6_addr prefix;
                struct rt6_info *rt;

                ipv6_addr_prefix(&prefix, &ifp->addr, ifp->prefix_len);

                rt = addrconf_get_prefix_route(&prefix,
                                               ifp->prefix_len,
                                               ifp->idev->dev,
                                               0, RTF_GATEWAY | RTF_DEFAULT);

                if (rt) {
                        if (onlink == 0) {
                                ip6_del_rt(rt);
                                rt = NULL;
                        } else if (!(rt->rt6i_flags & RTF_EXPIRES)) {
                                rt6_set_expires(rt, expires);
                        }
                }
                ip6_rt_put(rt);
        }

        /* clean up prefsrc entries */
        rt6_remove_prefsrc(ifp);
out:
        in6_ifa_put(ifp);
}

#ifdef CONFIG_IPV6_PRIVACY
static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, struct inet6_ifaddr *ift)
{
        struct inet6_dev *idev = ifp->idev;
        struct in6_addr addr, *tmpaddr;
        unsigned long tmp_prefered_lft, tmp_valid_lft, tmp_tstamp, age;
        unsigned long regen_advance;
        int tmp_plen;
        int ret = 0;
        int max_addresses;
        u32 addr_flags;
        unsigned long now = jiffies;

        write_lock(&idev->lock);
        if (ift) {
                spin_lock_bh(&ift->lock);
                memcpy(&addr.s6_addr[8], &ift->addr.s6_addr[8], 8);
                spin_unlock_bh(&ift->lock);
                tmpaddr = &addr;
        } else {
                tmpaddr = NULL;
        }
retry:
        in6_dev_hold(idev);
        if (idev->cnf.use_tempaddr <= 0) {
                write_unlock(&idev->lock);
                pr_info("%s: use_tempaddr is disabled\n", __func__);
                in6_dev_put(idev);
                ret = -1;
                goto out;
        }
        spin_lock_bh(&ifp->lock);
        if (ifp->regen_count++ >= idev->cnf.regen_max_retry) {
                idev->cnf.use_tempaddr = -1;    /*XXX*/
                spin_unlock_bh(&ifp->lock);
                write_unlock(&idev->lock);
                pr_warn("%s: regeneration time exceeded - disabled temporary address support\n",
                        __func__);
                in6_dev_put(idev);
                ret = -1;
                goto out;
        }
        in6_ifa_hold(ifp);
        memcpy(addr.s6_addr, ifp->addr.s6_addr, 8);
        __ipv6_try_regen_rndid(idev, tmpaddr);
        memcpy(&addr.s6_addr[8], idev->rndid, 8);
        age = (now - ifp->tstamp) / HZ;
        tmp_valid_lft = min_t(__u32,
                              ifp->valid_lft,
                              idev->cnf.temp_valid_lft + age);
        tmp_prefered_lft = min_t(__u32,
                                 ifp->prefered_lft,
                                 idev->cnf.temp_prefered_lft + age -
                                 idev->cnf.max_desync_factor);
        tmp_plen = ifp->prefix_len;
        max_addresses = idev->cnf.max_addresses;
        tmp_tstamp = ifp->tstamp;
        spin_unlock_bh(&ifp->lock);

        regen_advance = idev->cnf.regen_max_retry *
                        idev->cnf.dad_transmits *
                        idev->nd_parms->retrans_time / HZ;
        write_unlock(&idev->lock);

        /* A temporary address is created only if this calculated Preferred
         * Lifetime is greater than REGEN_ADVANCE time units.  In particular,
         * an implementation must not create a temporary address with a zero
         * Preferred Lifetime.
         */
        if (tmp_prefered_lft <= regen_advance) {
                in6_ifa_put(ifp);
                in6_dev_put(idev);
                ret = -1;
                goto out;
        }

        addr_flags = IFA_F_TEMPORARY;
        /* set in addrconf_prefix_rcv() */
        if (ifp->flags & IFA_F_OPTIMISTIC)
                addr_flags |= IFA_F_OPTIMISTIC;

        ift = !max_addresses ||
              ipv6_count_addresses(idev) < max_addresses ?
                ipv6_add_addr(idev, &addr, tmp_plen,
                              ipv6_addr_type(&addr)&IPV6_ADDR_SCOPE_MASK,
                              addr_flags) : NULL;
        if (IS_ERR_OR_NULL(ift)) {
                in6_ifa_put(ifp);
                in6_dev_put(idev);
                pr_info("%s: retry temporary address regeneration\n", __func__);
                tmpaddr = &addr;
                write_lock(&idev->lock);
                goto retry;
        }

        spin_lock_bh(&ift->lock);
        ift->ifpub = ifp;
        ift->valid_lft = tmp_valid_lft;
        ift->prefered_lft = tmp_prefered_lft;
        ift->cstamp = now;
        ift->tstamp = tmp_tstamp;
        spin_unlock_bh(&ift->lock);

        addrconf_dad_start(ift);
        in6_ifa_put(ift);
        in6_dev_put(idev);
out:
        return ret;
}
#endif

/*
 *      Choose an appropriate source address (RFC3484)
 */
enum {
        IPV6_SADDR_RULE_INIT = 0,
        IPV6_SADDR_RULE_LOCAL,
        IPV6_SADDR_RULE_SCOPE,
        IPV6_SADDR_RULE_PREFERRED,
#ifdef CONFIG_IPV6_MIP6
        IPV6_SADDR_RULE_HOA,
#endif
        IPV6_SADDR_RULE_OIF,
        IPV6_SADDR_RULE_LABEL,
#ifdef CONFIG_IPV6_PRIVACY
        IPV6_SADDR_RULE_PRIVACY,
#endif
        IPV6_SADDR_RULE_ORCHID,
        IPV6_SADDR_RULE_PREFIX,
        IPV6_SADDR_RULE_MAX
};

struct ipv6_saddr_score {
        int                     rule;
        int                     addr_type;
        struct inet6_ifaddr     *ifa;
        DECLARE_BITMAP(scorebits, IPV6_SADDR_RULE_MAX);
        int                     scopedist;
        int                     matchlen;
};

struct ipv6_saddr_dst {
        const struct in6_addr *addr;
        int ifindex;
        int scope;
        int label;
        unsigned int prefs;
};

static inline int ipv6_saddr_preferred(int type)
{
        if (type & (IPV6_ADDR_MAPPED|IPV6_ADDR_COMPATv4|IPV6_ADDR_LOOPBACK))
                return 1;
        return 0;
}

static int ipv6_get_saddr_eval(struct net *net,
                               struct ipv6_saddr_score *score,
                               struct ipv6_saddr_dst *dst,
                               int i)
{
        int ret;

        if (i <= score->rule) {
                switch (i) {
                case IPV6_SADDR_RULE_SCOPE:
                        ret = score->scopedist;
                        break;
                case IPV6_SADDR_RULE_PREFIX:
                        ret = score->matchlen;
                        break;
                default:
                        ret = !!test_bit(i, score->scorebits);
                }
                goto out;
        }

        switch (i) {
        case IPV6_SADDR_RULE_INIT:
                /* Rule 0: remember if hiscore is not ready yet */
                ret = !!score->ifa;
                break;
        case IPV6_SADDR_RULE_LOCAL:
                /* Rule 1: Prefer same address */
                ret = ipv6_addr_equal(&score->ifa->addr, dst->addr);
                break;
        case IPV6_SADDR_RULE_SCOPE:
                /* Rule 2: Prefer appropriate scope
                 *
                 *      ret
                 *       ^
                 *    -1 |  d 15
                 *    ---+--+-+---> scope
                 *       |
                 *       |             d is scope of the destination.
                 *  B-d  |  \
                 *       |   \      <- smaller scope is better if
                 *  B-15 |    \        if scope is enough for destinaion.
                 *       |             ret = B - scope (-1 <= scope >= d <= 15).
                 * d-C-1 | /
                 *       |/         <- greater is better
                 *   -C  /             if scope is not enough for destination.
                 *      /|             ret = scope - C (-1 <= d < scope <= 15).
                 *
                 * d - C - 1 < B -15 (for all -1 <= d <= 15).
                 * C > d + 14 - B >= 15 + 14 - B = 29 - B.
                 * Assume B = 0 and we get C > 29.
                 */
                ret = __ipv6_addr_src_scope(score->addr_type);
                if (ret >= dst->scope)
                        ret = -ret;
                else
                        ret -= 128;     /* 30 is enough */
                score->scopedist = ret;
                break;
        case IPV6_SADDR_RULE_PREFERRED:
                /* Rule 3: Avoid deprecated and optimistic addresses */
                ret = ipv6_saddr_preferred(score->addr_type) ||
                      !(score->ifa->flags & (IFA_F_DEPRECATED|IFA_F_OPTIMISTIC));
                break;
#ifdef CONFIG_IPV6_MIP6
        case IPV6_SADDR_RULE_HOA:
            {
                /* Rule 4: Prefer home address */
                int prefhome = !(dst->prefs & IPV6_PREFER_SRC_COA);
                ret = !(score->ifa->flags & IFA_F_HOMEADDRESS) ^ prefhome;
                break;
            }
#endif
        case IPV6_SADDR_RULE_OIF:
                /* Rule 5: Prefer outgoing interface */
                ret = (!dst->ifindex ||
                       dst->ifindex == score->ifa->idev->dev->ifindex);
                break;
        case IPV6_SADDR_RULE_LABEL:
                /* Rule 6: Prefer matching label */
                ret = ipv6_addr_label(net,
                                      &score->ifa->addr, score->addr_type,
                                      score->ifa->idev->dev->ifindex) == dst->label;
                break;
#ifdef CONFIG_IPV6_PRIVACY
        case IPV6_SADDR_RULE_PRIVACY:
            {
                /* Rule 7: Prefer public address
                 * Note: prefer temporary address if use_tempaddr >= 2
                 */
                int preftmp = dst->prefs & (IPV6_PREFER_SRC_PUBLIC|IPV6_PREFER_SRC_TMP) ?
                                !!(dst->prefs & IPV6_PREFER_SRC_TMP) :
                                score->ifa->idev->cnf.use_tempaddr >= 2;
                ret = (!(score->ifa->flags & IFA_F_TEMPORARY)) ^ preftmp;
                break;
            }
#endif
        case IPV6_SADDR_RULE_ORCHID:
                /* Rule 8-: Prefer ORCHID vs ORCHID or
                 *          non-ORCHID vs non-ORCHID
                 */
                ret = !(ipv6_addr_orchid(&score->ifa->addr) ^
                        ipv6_addr_orchid(dst->addr));
                break;
        case IPV6_SADDR_RULE_PREFIX:
                /* Rule 8: Use longest matching prefix */
                ret = ipv6_addr_diff(&score->ifa->addr, dst->addr);
                if (ret > score->ifa->prefix_len)
                        ret = score->ifa->prefix_len;
                score->matchlen = ret;
                break;
        default:
                ret = 0;
        }

        if (ret)
                __set_bit(i, score->scorebits);
        score->rule = i;
out:
        return ret;
}

int ipv6_dev_get_saddr(struct net *net, const struct net_device *dst_dev,
                       const struct in6_addr *daddr, unsigned int prefs,
                       struct in6_addr *saddr)
{
        struct ipv6_saddr_score scores[2],
                                *score = &scores[0], *hiscore = &scores[1];
        struct ipv6_saddr_dst dst;
        struct net_device *dev;
        int dst_type;

        dst_type = __ipv6_addr_type(daddr);
        dst.addr = daddr;
        dst.ifindex = dst_dev ? dst_dev->ifindex : 0;
        dst.scope = __ipv6_addr_src_scope(dst_type);
        dst.label = ipv6_addr_label(net, daddr, dst_type, dst.ifindex);
        dst.prefs = prefs;

        hiscore->rule = -1;
        hiscore->ifa = NULL;

        rcu_read_lock();

        for_each_netdev_rcu(net, dev) {
                struct inet6_dev *idev;

                /* Candidate Source Address (section 4)
                 *  - multicast and link-local destination address,
                 *    the set of candidate source address MUST only
                 *    include addresses assigned to interfaces
                 *    belonging to the same link as the outgoing
                 *    interface.
                 * (- For site-local destination addresses, the
                 *    set of candidate source addresses MUST only
                 *    include addresses assigned to interfaces
                 *    belonging to the same site as the outgoing
                 *    interface.)
                 */
                if (((dst_type & IPV6_ADDR_MULTICAST) ||
                     dst.scope <= IPV6_ADDR_SCOPE_LINKLOCAL) &&
                    dst.ifindex && dev->ifindex != dst.ifindex)
                        continue;

                idev = __in6_dev_get(dev);
                if (!idev)
                        continue;

                read_lock_bh(&idev->lock);
                list_for_each_entry(score->ifa, &idev->addr_list, if_list) {
                        int i;

                        /*
                         * - Tentative Address (RFC2462 section 5.4)
                         *  - A tentative address is not considered
                         *    "assigned to an interface" in the traditional
                         *    sense, unless it is also flagged as optimistic.
                         * - Candidate Source Address (section 4)
                         *  - In any case, anycast addresses, multicast
                         *    addresses, and the unspecified address MUST
                         *    NOT be included in a candidate set.
                         */
                        if ((score->ifa->flags & IFA_F_TENTATIVE) &&
                            (!(score->ifa->flags & IFA_F_OPTIMISTIC)))
                                continue;

                        score->addr_type = __ipv6_addr_type(&score->ifa->addr);

                        if (unlikely(score->addr_type == IPV6_ADDR_ANY ||
                                     score->addr_type & IPV6_ADDR_MULTICAST)) {
                                LIMIT_NETDEBUG(KERN_DEBUG
                                               "ADDRCONF: unspecified / multicast address "
                                               "assigned as unicast address on %s",
                                               dev->name);
                                continue;
                        }

                        score->rule = -1;
                        bitmap_zero(score->scorebits, IPV6_SADDR_RULE_MAX);

                        for (i = 0; i < IPV6_SADDR_RULE_MAX; i++) {
                                int minihiscore, miniscore;

                                minihiscore = ipv6_get_saddr_eval(net, hiscore, &dst, i);
                                miniscore = ipv6_get_saddr_eval(net, score, &dst, i);

                                if (minihiscore > miniscore) {
                                        if (i == IPV6_SADDR_RULE_SCOPE &&
                                            score->scopedist > 0) {
                                                /*
                                                 * special case:
                                                 * each remaining entry
                                                 * has too small (not enough)
                                                 * scope, because ifa entries
                                                 * are sorted by their scope
                                                 * values.
                                                 */
                                                goto try_nextdev;
                                        }
                                        break;
                                } else if (minihiscore < miniscore) {
                                        if (hiscore->ifa)
                                                in6_ifa_put(hiscore->ifa);

                                        in6_ifa_hold(score->ifa);

                                        swap(hiscore, score);

                                        /* restore our iterator */
                                        score->ifa = hiscore->ifa;

                                        break;
                                }
                        }
                }
try_nextdev:
                read_unlock_bh(&idev->lock);
        }
        rcu_read_unlock();

        if (!hiscore->ifa)
                return -EADDRNOTAVAIL;

        *saddr = hiscore->ifa->addr;
        in6_ifa_put(hiscore->ifa);
        return 0;
}
EXPORT_SYMBOL(ipv6_dev_get_saddr);

int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr,
                    unsigned char banned_flags)
{
        struct inet6_dev *idev;
        int err = -EADDRNOTAVAIL;

        rcu_read_lock();
        idev = __in6_dev_get(dev);
        if (idev) {
                struct inet6_ifaddr *ifp;

                read_lock_bh(&idev->lock);
                list_for_each_entry(ifp, &idev->addr_list, if_list) {
                        if (ifp->scope == IFA_LINK &&
                            !(ifp->flags & banned_flags)) {
                                *addr = ifp->addr;
                                err = 0;
                                break;
                        }
                }
                read_unlock_bh(&idev->lock);
        }
        rcu_read_unlock();
        return err;
}

static int ipv6_count_addresses(struct inet6_dev *idev)
{
        int cnt = 0;
        struct inet6_ifaddr *ifp;

        read_lock_bh(&idev->lock);
        list_for_each_entry(ifp, &idev->addr_list, if_list)
                cnt++;
        read_unlock_bh(&idev->lock);
        return cnt;
}

int ipv6_chk_addr(struct net *net, const struct in6_addr *addr,
                  const struct net_device *dev, int strict)
{
        struct inet6_ifaddr *ifp;
        unsigned int hash = inet6_addr_hash(addr);

        rcu_read_lock_bh();
        hlist_for_each_entry_rcu(ifp, &inet6_addr_lst[hash], addr_lst) {
                if (!net_eq(dev_net(ifp->idev->dev), net))
                        continue;
                if (ipv6_addr_equal(&ifp->addr, addr) &&
                    !(ifp->flags&IFA_F_TENTATIVE) &&
                    (dev == NULL || ifp->idev->dev == dev ||
                     !(ifp->scope&(IFA_LINK|IFA_HOST) || strict))) {
                        rcu_read_unlock_bh();
                        return 1;
                }
        }

        rcu_read_unlock_bh();
        return 0;
}
EXPORT_SYMBOL(ipv6_chk_addr);

static bool ipv6_chk_same_addr(struct net *net, const struct in6_addr *addr,
                               struct net_device *dev)
{
        unsigned int hash = inet6_addr_hash(addr);
        struct inet6_ifaddr *ifp;

        hlist_for_each_entry(ifp, &inet6_addr_lst[hash], addr_lst) {
                if (!net_eq(dev_net(ifp->idev->dev), net))
                        continue;
                if (ipv6_addr_equal(&ifp->addr, addr)) {
                        if (dev == NULL || ifp->idev->dev == dev)
                                return true;
                }
        }
        return false;
}

int ipv6_chk_prefix(const struct in6_addr *addr, struct net_device *dev)
{
        struct inet6_dev *idev;
        struct inet6_ifaddr *ifa;
        int     onlink;

        onlink = 0;
        rcu_read_lock();
        idev = __in6_dev_get(dev);
        if (idev) {
                read_lock_bh(&idev->lock);
                list_for_each_entry(ifa, &idev->addr_list, if_list) {
                        onlink = ipv6_prefix_equal(addr, &ifa->addr,
                                                   ifa->prefix_len);
                        if (onlink)
                                break;
                }
                read_unlock_bh(&idev->lock);
        }
        rcu_read_unlock();
        return onlink;
}
EXPORT_SYMBOL(ipv6_chk_prefix);

struct inet6_ifaddr *ipv6_get_ifaddr(struct net *net, const struct in6_addr *addr,
                                     struct net_device *dev, int strict)
{
        struct inet6_ifaddr *ifp, *result = NULL;
        unsigned int hash = inet6_addr_hash(addr);

        rcu_read_lock_bh();
        hlist_for_each_entry_rcu_bh(ifp, &inet6_addr_lst[hash], addr_lst) {
                if (!net_eq(dev_net(ifp->idev->dev), net))
                        continue;
                if (ipv6_addr_equal(&ifp->addr, addr)) {
                        if (dev == NULL || ifp->idev->dev == dev ||
                            !(ifp->scope&(IFA_LINK|IFA_HOST) || strict)) {
                                result = ifp;
                                in6_ifa_hold(ifp);
                                break;
                        }
                }
        }
        rcu_read_unlock_bh();

        return result;
}

/* Gets referenced address, destroys ifaddr */

static void addrconf_dad_stop(struct inet6_ifaddr *ifp, int dad_failed)
{
        if (ifp->flags&IFA_F_PERMANENT) {
                spin_lock_bh(&ifp->lock);
                addrconf_del_timer(ifp);
                ifp->flags |= IFA_F_TENTATIVE;
                if (dad_failed)
                        ifp->flags |= IFA_F_DADFAILED;
                spin_unlock_bh(&ifp->lock);
                if (dad_failed)
                        ipv6_ifa_notify(0, ifp);
                in6_ifa_put(ifp);
#ifdef CONFIG_IPV6_PRIVACY
        } else if (ifp->flags&IFA_F_TEMPORARY) {
                struct inet6_ifaddr *ifpub;
                spin_lock_bh(&ifp->lock);
                ifpub = ifp->ifpub;
                if (ifpub) {
                        in6_ifa_hold(ifpub);
                        spin_unlock_bh(&ifp->lock);
                        ipv6_create_tempaddr(ifpub, ifp);
                        in6_ifa_put(ifpub);
                } else {
                        spin_unlock_bh(&ifp->lock);
                }
                ipv6_del_addr(ifp);
#endif
        } else
                ipv6_del_addr(ifp);
}

static int addrconf_dad_end(struct inet6_ifaddr *ifp)
{
        int err = -ENOENT;

        spin_lock(&ifp->state_lock);
        if (ifp->state == INET6_IFADDR_STATE_DAD) {
                ifp->state = INET6_IFADDR_STATE_POSTDAD;
                err = 0;
        }
        spin_unlock(&ifp->state_lock);

        return err;
}

void addrconf_dad_failure(struct inet6_ifaddr *ifp)
{
        struct inet6_dev *idev = ifp->idev;

        if (addrconf_dad_end(ifp)) {
                in6_ifa_put(ifp);
                return;
        }

        net_info_ratelimited("%s: IPv6 duplicate address %pI6c detected!\n",
                             ifp->idev->dev->name, &ifp->addr);

        if (idev->cnf.accept_dad > 1 && !idev->cnf.disable_ipv6) {
                struct in6_addr addr;

                addr.s6_addr32[0] = htonl(0xfe800000);
                addr.s6_addr32[1] = 0;

                if (!ipv6_generate_eui64(addr.s6_addr + 8, idev->dev) &&
                    ipv6_addr_equal(&ifp->addr, &addr)) {
                        /* DAD failed for link-local based on MAC address */
                        idev->cnf.disable_ipv6 = 1;

                        pr_info("%s: IPv6 being disabled!\n",
                                ifp->idev->dev->name);
                }
        }

        addrconf_dad_stop(ifp, 1);
}

/* Join to solicited addr multicast group. */

void addrconf_join_solict(struct net_device *dev, const struct in6_addr *addr)
{
        struct in6_addr maddr;

        if (dev->flags&(IFF_LOOPBACK|IFF_NOARP))
                return;

        addrconf_addr_solict_mult(addr, &maddr);
        ipv6_dev_mc_inc(dev, &maddr);
}

void addrconf_leave_solict(struct inet6_dev *idev, const struct in6_addr *addr)
{
        struct in6_addr maddr;

        if (idev->dev->flags&(IFF_LOOPBACK|IFF_NOARP))
                return;

        addrconf_addr_solict_mult(addr, &maddr);
        __ipv6_dev_mc_dec(idev, &maddr);
}

static void addrconf_join_anycast(struct inet6_ifaddr *ifp)
{
        struct in6_addr addr;
        if (ifp->prefix_len == 127) /* RFC 6164 */
                return;
        ipv6_addr_prefix(&addr, &ifp->addr, ifp->prefix_len);
        if (ipv6_addr_any(&addr))
                return;
        ipv6_dev_ac_inc(ifp->idev->dev, &addr);
}

static void addrconf_leave_anycast(struct inet6_ifaddr *ifp)
{
        struct in6_addr addr;
        if (ifp->prefix_len == 127) /* RFC 6164 */
                return;
        ipv6_addr_prefix(&addr, &ifp->addr, ifp->prefix_len);
        if (ipv6_addr_any(&addr))
                return;
        __ipv6_dev_ac_dec(ifp->idev, &addr);
}

static int addrconf_ifid_eui48(u8 *eui, struct net_device *dev)
{
        if (dev->addr_len != ETH_ALEN)
                return -1;
        memcpy(eui, dev->dev_addr, 3);
        memcpy(eui + 5, dev->dev_addr + 3, 3);

        /*
         * The zSeries OSA network cards can be shared among various
         * OS instances, but the OSA cards have only one MAC address.
         * This leads to duplicate address conflicts in conjunction
         * with IPv6 if more than one instance uses the same card.
         *
         * The driver for these cards can deliver a unique 16-bit
         * identifier for each instance sharing the same card.  It is
         * placed instead of 0xFFFE in the interface identifier.  The
         * "u" bit of the interface identifier is not inverted in this
         * case.  Hence the resulting interface identifier has local
         * scope according to RFC2373.
         */
        if (dev->dev_id) {
                eui[3] = (dev->dev_id >> 8) & 0xFF;
                eui[4] = dev->dev_id & 0xFF;
        } else {
                eui[3] = 0xFF;
                eui[4] = 0xFE;
                eui[0] ^= 2;
        }
        return 0;
}

static int addrconf_ifid_eui64(u8 *eui, struct net_device *dev)
{
        if (dev->addr_len != IEEE802154_ADDR_LEN)
                return -1;
        memcpy(eui, dev->dev_addr, 8);
        eui[0] ^= 2;
        return 0;
}

static int addrconf_ifid_ieee1394(u8 *eui, struct net_device *dev)
{
        union fwnet_hwaddr *ha;

        if (dev->addr_len != FWNET_ALEN)
                return -1;

        ha = (union fwnet_hwaddr *)dev->dev_addr;

        memcpy(eui, &ha->uc.uniq_id, sizeof(ha->uc.uniq_id));
        eui[0] ^= 2;
        return 0;
}

static int addrconf_ifid_arcnet(u8 *eui, struct net_device *dev)
{
        /* XXX: inherit EUI-64 from other interface -- yoshfuji */
        if (dev->addr_len != ARCNET_ALEN)
                return -1;
        memset(eui, 0, 7);
        eui[7] = *(u8 *)dev->dev_addr;
        return 0;
}

static int addrconf_ifid_infiniband(u8 *eui, struct net_device *dev)
{
        if (dev->addr_len != INFINIBAND_ALEN)
                return -1;
        memcpy(eui, dev->dev_addr + 12, 8);
        eui[0] |= 2;
        return 0;
}

static int __ipv6_isatap_ifid(u8 *eui, __be32 addr)
{
        if (addr == 0)
                return -1;
        eui[0] = (ipv4_is_zeronet(addr) || ipv4_is_private_10(addr) ||
                  ipv4_is_loopback(addr) || ipv4_is_linklocal_169(addr) ||
                  ipv4_is_private_172(addr) || ipv4_is_test_192(addr) ||
                  ipv4_is_anycast_6to4(addr) || ipv4_is_private_192(addr) ||
                  ipv4_is_test_198(addr) || ipv4_is_multicast(addr) ||
                  ipv4_is_lbcast(addr)) ? 0x00 : 0x02;
        eui[1] = 0;
        eui[2] = 0x5E;
        eui[3] = 0xFE;
        memcpy(eui + 4, &addr, 4);
        return 0;
}

static int addrconf_ifid_sit(u8 *eui, struct net_device *dev)
{
        if (dev->priv_flags & IFF_ISATAP)
                return __ipv6_isatap_ifid(eui, *(__be32 *)dev->dev_addr);
        return -1;
}

static int addrconf_ifid_gre(u8 *eui, struct net_device *dev)
{
        return __ipv6_isatap_ifid(eui, *(__be32 *)dev->dev_addr);
}

static int ipv6_generate_eui64(u8 *eui, struct net_device *dev)
{
        switch (dev->type) {
        case ARPHRD_ETHER:
        case ARPHRD_FDDI:
                return addrconf_ifid_eui48(eui, dev);
        case ARPHRD_ARCNET:
                return addrconf_ifid_arcnet(eui, dev);
        case ARPHRD_INFINIBAND:
                return addrconf_ifid_infiniband(eui, dev);
        case ARPHRD_SIT:
                return addrconf_ifid_sit(eui, dev);
        case ARPHRD_IPGRE:
                return addrconf_ifid_gre(eui, dev);
        case ARPHRD_IEEE802154:
                return addrconf_ifid_eui64(eui, dev);
        case ARPHRD_IEEE1394:
                return addrconf_ifid_ieee1394(eui, dev);
        }
        return -1;
}

static int ipv6_inherit_eui64(u8 *eui, struct inet6_dev *idev)
{
        int err = -1;
        struct inet6_ifaddr *ifp;

        read_lock_bh(&idev->lock);
        list_for_each_entry(ifp, &idev->addr_list, if_list) {
                if (ifp->scope == IFA_LINK && !(ifp->flags&IFA_F_TENTATIVE)) {
                        memcpy(eui, ifp->addr.s6_addr+8, 8);
                        err = 0;
                        break;
                }
        }
        read_unlock_bh(&idev->lock);
        return err;
}

#ifdef CONFIG_IPV6_PRIVACY
/* (re)generation of randomized interface identifier (RFC 3041 3.2, 3.5) */
static void __ipv6_regen_rndid(struct inet6_dev *idev)
{
regen:
        get_random_bytes(idev->rndid, sizeof(idev->rndid));
        idev->rndid[0] &= ~0x02;

        /*
         * <draft-ietf-ipngwg-temp-addresses-v2-00.txt>:
         * check if generated address is not inappropriate
         *
         *  - Reserved subnet anycast (RFC 2526)
         *      11111101 11....11 1xxxxxxx
         *  - ISATAP (RFC4214) 6.1
         *      00-00-5E-FE-xx-xx-xx-xx
         *  - value 0
         *  - XXX: already assigned to an address on the device
         */
        if (idev->rndid[0] == 0xfd &&
            (idev->rndid[1]&idev->rndid[2]&idev->rndid[3]&idev->rndid[4]&idev->rndid[5]&idev->rndid[6]) == 0xff &&
            (idev->rndid[7]&0x80))
                goto regen;
        if ((idev->rndid[0]|idev->rndid[1]) == 0) {
                if (idev->rndid[2] == 0x5e && idev->rndid[3] == 0xfe)
                        goto regen;
                if ((idev->rndid[2]|idev->rndid[3]|idev->rndid[4]|idev->rndid[5]|idev->rndid[6]|idev->rndid[7]) == 0x00)
                        goto regen;
        }
}

static void ipv6_regen_rndid(unsigned long data)
{
        struct inet6_dev *idev = (struct inet6_dev *) data;
        unsigned long expires;

        rcu_read_lock_bh();
        write_lock_bh(&idev->lock);

        if (idev->dead)
                goto out;

        __ipv6_regen_rndid(idev);

        expires = jiffies +
                idev->cnf.temp_prefered_lft * HZ -
                idev->cnf.regen_max_retry * idev->cnf.dad_transmits * idev->nd_parms->retrans_time -
                idev->cnf.max_desync_factor * HZ;
        if (time_before(expires, jiffies)) {
                pr_warn("%s: too short regeneration interval; timer disabled for %s\n",
                        __func__, idev->dev->name);
                goto out;
        }

        if (!mod_timer(&idev->regen_timer, expires))
                in6_dev_hold(idev);

out:
        write_unlock_bh(&idev->lock);
        rcu_read_unlock_bh();
        in6_dev_put(idev);
}

static void  __ipv6_try_regen_rndid(struct inet6_dev *idev, struct in6_addr *tmpaddr)
{
        if (tmpaddr && memcmp(idev->rndid, &tmpaddr->s6_addr[8], 8) == 0)
                __ipv6_regen_rndid(idev);
}
#endif

/*
 *      Add prefix route.
 */

static void
addrconf_prefix_route(struct in6_addr *pfx, int plen, struct net_device *dev,
                      unsigned long expires, u32 flags)
{
        struct fib6_config cfg = {
                .fc_table = RT6_TABLE_PREFIX,
                .fc_metric = IP6_RT_PRIO_ADDRCONF,
                .fc_ifindex = dev->ifindex,
                .fc_expires = expires,
                .fc_dst_len = plen,
                .fc_flags = RTF_UP | flags,
                .fc_nlinfo.nl_net = dev_net(dev),
                .fc_protocol = RTPROT_KERNEL,
        };

        cfg.fc_dst = *pfx;

        /* Prevent useless cloning on PtP SIT.
           This thing is done here expecting that the whole
           class of non-broadcast devices need not cloning.
         */
#if IS_ENABLED(CONFIG_IPV6_SIT)
        if (dev->type == ARPHRD_SIT && (dev->flags & IFF_POINTOPOINT))
                cfg.fc_flags |= RTF_NONEXTHOP;
#endif

        ip6_route_add(&cfg);
}


static struct rt6_info *addrconf_get_prefix_route(const struct in6_addr *pfx,
                                                  int plen,
                                                  const struct net_device *dev,
                                                  u32 flags, u32 noflags)
{
        struct fib6_node *fn;
        struct rt6_info *rt = NULL;
        struct fib6_table *table;

        table = fib6_get_table(dev_net(dev), RT6_TABLE_PREFIX);
        if (table == NULL)
                return NULL;

        read_lock_bh(&table->tb6_lock);
        fn = fib6_locate(&table->tb6_root, pfx, plen, NULL, 0);
        if (!fn)
                goto out;
        for (rt = fn->leaf; rt; rt = rt->dst.rt6_next) {
                if (rt->dst.dev->ifindex != dev->ifindex)
                        continue;
                if ((rt->rt6i_flags & flags) != flags)
                        continue;
                if ((rt->rt6i_flags & noflags) != 0)
                        continue;
                dst_hold(&rt->dst);
                break;
        }
out:
        read_unlock_bh(&table->tb6_lock);
        return rt;
}


/* Create "default" multicast route to the interface */

static void addrconf_add_mroute(struct net_device *dev)
{
        struct fib6_config cfg = {
                .fc_table = RT6_TABLE_LOCAL,
                .fc_metric = IP6_RT_PRIO_ADDRCONF,
                .fc_ifindex = dev->ifindex,
                .fc_dst_len = 8,
                .fc_flags = RTF_UP,
                .fc_nlinfo.nl_net = dev_net(dev),
        };

        ipv6_addr_set(&cfg.fc_dst, htonl(0xFF000000), 0, 0, 0);

        ip6_route_add(&cfg);
}

#if IS_ENABLED(CONFIG_IPV6_SIT)
static void sit_route_add(struct net_device *dev)
{

        struct fib6_config cfg = {
                .fc_table = RT6_TABLE_MAIN,
                .fc_metric = IP6_RT_PRIO_ADDRCONF,
                .fc_ifindex = dev->ifindex,
                .fc_dst_len = 96,
                .fc_flags = RTF_UP | RTF_NONEXTHOP,
                .fc_nlinfo.nl_net = dev_net(dev),
        };

        /* prefix length - 96 bits "::d.d.d.d" */
        ip6_route_add(&cfg);
}
#endif

static struct inet6_dev *addrconf_add_dev(struct net_device *dev)
{
        struct inet6_dev *idev;

        ASSERT_RTNL();

        idev = ipv6_find_idev(dev);
        if (!idev)
                return ERR_PTR(-ENOBUFS);

        if (idev->cnf.disable_ipv6)
                return ERR_PTR(-EACCES);

        /* Add default multicast route */
        if (!(dev->flags & IFF_LOOPBACK))
                addrconf_add_mroute(dev);

        return idev;
}

void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
{
        struct prefix_info *pinfo;
        __u32 valid_lft;
        __u32 prefered_lft;
        int addr_type;
        struct inet6_dev *in6_dev;
        struct net *net = dev_net(dev);

        pinfo = (struct prefix_info *) opt;

        if (len < sizeof(struct prefix_info)) {
                ADBG(("addrconf: prefix option too short\n"));
                return;
        }

        /*
         *      Validation checks ([ADDRCONF], page 19)
         */

        addr_type = ipv6_addr_type(&pinfo->prefix);

        if (addr_type & (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL))
                return;

        valid_lft = ntohl(pinfo->valid);
        prefered_lft = ntohl(pinfo->prefered);

        if (prefered_lft > valid_lft) {
                net_warn_ratelimited("addrconf: prefix option has invalid lifetime\n");
                return;
        }

        in6_dev = in6_dev_get(dev);

        if (in6_dev == NULL) {
                net_dbg_ratelimited("addrconf: device %s not configured\n",
                                    dev->name);
                return;
        }

        /*
         *      Two things going on here:
         *      1) Add routes for on-link prefixes
         *      2) Configure prefixes with the auto flag set
         */

        if (pinfo->onlink) {
                struct rt6_info *rt;
                unsigned long rt_expires;

                /* Avoid arithmetic overflow. Really, we could
                 * save rt_expires in seconds, likely valid_lft,
                 * but it would require division in fib gc, that it
                 * not good.
                 */
                if (HZ > USER_HZ)
                        rt_expires = addrconf_timeout_fixup(valid_lft, HZ);
                else
                        rt_expires = addrconf_timeout_fixup(valid_lft, USER_HZ);

                if (addrconf_finite_timeout(rt_expires))
                        rt_expires *= HZ;

                rt = addrconf_get_prefix_route(&pinfo->prefix,
                                               pinfo->prefix_len,
                                               dev,
                                               RTF_ADDRCONF | RTF_PREFIX_RT,
                                               RTF_GATEWAY | RTF_DEFAULT);

                if (rt) {
                        /* Autoconf prefix route */
                        if (valid_lft == 0) {
                                ip6_del_rt(rt);
                                rt = NULL;
                        } else if (addrconf_finite_timeout(rt_expires)) {
                                /* not infinity */
                                rt6_set_expires(rt, jiffies + rt_expires);
                        } else {
                                rt6_clean_expires(rt);
                        }
                } else if (valid_lft) {
                        clock_t expires = 0;
                        int flags = RTF_ADDRCONF | RTF_PREFIX_RT;
                        if (addrconf_finite_timeout(rt_expires)) {
                                /* not infinity */
                                flags |= RTF_EXPIRES;
                                expires = jiffies_to_clock_t(rt_expires);
                        }
                        addrconf_prefix_route(&pinfo->prefix, pinfo->prefix_len,
                                              dev, expires, flags);
                }
                ip6_rt_put(rt);
        }

        /* Try to figure out our local address for this prefix */

        if (pinfo->autoconf && in6_dev->cnf.autoconf) {
                struct inet6_ifaddr *ifp;
                struct in6_addr addr;
                int create = 0, update_lft = 0;
                bool tokenized = false;

                if (pinfo->prefix_len == 64) {
                        memcpy(&addr, &pinfo->prefix, 8);

                        if (!ipv6_addr_any(&in6_dev->token)) {
                                read_lock_bh(&in6_dev->lock);
                                memcpy(addr.s6_addr + 8,
                                       in6_dev->token.s6_addr + 8, 8);
                                read_unlock_bh(&in6_dev->lock);
                                tokenized = true;
                        } else if (ipv6_generate_eui64(addr.s6_addr + 8, dev) &&
                                   ipv6_inherit_eui64(addr.s6_addr + 8, in6_dev)) {
                                in6_dev_put(in6_dev);
                                return;
                        }
                        goto ok;
                }
                net_dbg_ratelimited("IPv6 addrconf: prefix with wrong length %d\n",
                                    pinfo->prefix_len);
                in6_dev_put(in6_dev);
                return;

ok:

                ifp = ipv6_get_ifaddr(net, &addr, dev, 1);

                if (ifp == NULL && valid_lft) {
                        int max_addresses = in6_dev->cnf.max_addresses;
                        u32 addr_flags = 0;

#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
                        if (in6_dev->cnf.optimistic_dad &&
                            !net->ipv6.devconf_all->forwarding && sllao)
                                addr_flags = IFA_F_OPTIMISTIC;
#endif

                        /* Do not allow to create too much of autoconfigured
                         * addresses; this would be too easy way to crash kernel.
                         */
                        if (!max_addresses ||
                            ipv6_count_addresses(in6_dev) < max_addresses)
                                ifp = ipv6_add_addr(in6_dev, &addr, pinfo->prefix_len,
                                                    addr_type&IPV6_ADDR_SCOPE_MASK,
                                                    addr_flags);

                        if (IS_ERR_OR_NULL(ifp)) {
                                in6_dev_put(in6_dev);
                                return;
                        }

                        update_lft = create = 1;
                        ifp->cstamp = jiffies;
                        ifp->tokenized = tokenized;
                        addrconf_dad_start(ifp);
                }

                if (ifp) {
                        int flags;
                        unsigned long now;
#ifdef CONFIG_IPV6_PRIVACY
                        struct inet6_ifaddr *ift;
#endif
                        u32 stored_lft;

                        /* update lifetime (RFC2462 5.5.3 e) */
                        spin_lock(&ifp->lock);
                        now = jiffies;
                        if (ifp->valid_lft > (now - ifp->tstamp) / HZ)
                                stored_lft = ifp->valid_lft - (now - ifp->tstamp) / HZ;
                        else
                                stored_lft = 0;
                        if (!update_lft && stored_lft) {
                                if (valid_lft > MIN_VALID_LIFETIME ||
                                    valid_lft > stored_lft)
                                        update_lft = 1;
                                else if (stored_lft <= MIN_VALID_LIFETIME) {
                                        /* valid_lft <= stored_lft is always true */
                                        /*
                                         * RFC 4862 Section 5.5.3e:
                                         * "Note that the preferred lifetime of
                                         *  the corresponding address is always
                                         *  reset to the Preferred Lifetime in
                                         *  the received Prefix Information
                                         *  option, regardless of whether the
                                         *  valid lifetime is also reset or
                                         *  ignored."
                                         *
                                         *  So if the preferred lifetime in
                                         *  this advertisement is different
                                         *  than what we have stored, but the
                                         *  valid lifetime is invalid, just
                                         *  reset prefered_lft.
                                         *
                                         *  We must set the valid lifetime
                                         *  to the stored lifetime since we'll
                                         *  be updating the timestamp below,
                                         *  else we'll set it back to the
                                         *  minimum.
                                         */
                                        if (prefered_lft != ifp->prefered_lft) {
                                                valid_lft = stored_lft;
                                                update_lft = 1;
                                        }
                                } else {
                                        valid_lft = MIN_VALID_LIFETIME;
                                        if (valid_lft < prefered_lft)
                                                prefered_lft = valid_lft;
                                        update_lft = 1;
                                }
                        }

                        if (update_lft) {
                                ifp->valid_lft = valid_lft;
                                ifp->prefered_lft = prefered_lft;
                                ifp->tstamp = now;
                                flags = ifp->flags;
                                ifp->flags &= ~IFA_F_DEPRECATED;
                                spin_unlock(&ifp->lock);

                                if (!(flags&IFA_F_TENTATIVE))
                                        ipv6_ifa_notify(0, ifp);
                        } else
                                spin_unlock(&ifp->lock);

#ifdef CONFIG_IPV6_PRIVACY
                        read_lock_bh(&in6_dev->lock);
                        /* update all temporary addresses in the list */
                        list_for_each_entry(ift, &in6_dev->tempaddr_list,
                                            tmp_list) {
                                int age, max_valid, max_prefered;

                                if (ifp != ift->ifpub)
                                        continue;

                                /*
                                 * RFC 4941 section 3.3:
                                 * If a received option will extend the lifetime
                                 * of a public address, the lifetimes of
                                 * temporary addresses should be extended,
                                 * subject to the overall constraint that no
                                 * temporary addresses should ever remain
                                 * "valid" or "preferred" for a time longer than
                                 * (TEMP_VALID_LIFETIME) or
                                 * (TEMP_PREFERRED_LIFETIME - DESYNC_FACTOR),
                                 * respectively.
                                 */
                                age = (now - ift->cstamp) / HZ;
                                max_valid = in6_dev->cnf.temp_valid_lft - age;
                                if (max_valid < 0)
                                        max_valid = 0;

                                max_prefered = in6_dev->cnf.temp_prefered_lft -
                                               in6_dev->cnf.max_desync_factor -
                                               age;
                                if (max_prefered < 0)
                                        max_prefered = 0;

                                if (valid_lft > max_valid)
                                        valid_lft = max_valid;

                                if (prefered_lft > max_prefered)
                                        prefered_lft = max_prefered;

                                spin_lock(&ift->lock);
                                flags = ift->flags;
                                ift->valid_lft = valid_lft;
                                ift->prefered_lft = prefered_lft;
                                ift->tstamp = now;
                                if (prefered_lft > 0)
                                        ift->flags &= ~IFA_F_DEPRECATED;

                                spin_unlock(&ift->lock);
                                if (!(flags&IFA_F_TENTATIVE))
                                        ipv6_ifa_notify(0, ift);
                        }

                        if ((create || list_empty(&in6_dev->tempaddr_list)) && in6_dev->cnf.use_tempaddr > 0) {
                                /*
                                 * When a new public address is created as
                                 * described in [ADDRCONF], also create a new
                                 * temporary address. Also create a temporary
                                 * address if it's enabled but no temporary
                                 * address currently exists.
                                 */
                                read_unlock_bh(&in6_dev->lock);
                                ipv6_create_tempaddr(ifp, NULL);
                        } else {
                                read_unlock_bh(&in6_dev->lock);
                        }
#endif
                        in6_ifa_put(ifp);
                        addrconf_verify(0);
                }
        }
        inet6_prefix_notify(RTM_NEWPREFIX, in6_dev, pinfo);
        in6_dev_put(in6_dev);
}

/*
 *      Set destination address.
 *      Special case for SIT interfaces where we create a new "virtual"
 *      device.
 */
int addrconf_set_dstaddr(struct net *net, void __user *arg)
{
        struct in6_ifreq ireq;
        struct net_device *dev;
        int err = -EINVAL;

        rtnl_lock();

        err = -EFAULT;
        if (copy_from_user(&ireq, arg, sizeof(struct in6_ifreq)))
                goto err_exit;

        dev = __dev_get_by_index(net, ireq.ifr6_ifindex);

        err = -ENODEV;
        if (dev == NULL)
                goto err_exit;

#if IS_ENABLED(CONFIG_IPV6_SIT)
        if (dev->type == ARPHRD_SIT) {
                const struct net_device_ops *ops = dev->netdev_ops;
                struct ifreq ifr;
                struct ip_tunnel_parm p;

                err = -EADDRNOTAVAIL;
                if (!(ipv6_addr_type(&ireq.ifr6_addr) & IPV6_ADDR_COMPATv4))
                        goto err_exit;

                memset(&p, 0, sizeof(p));
                p.iph.daddr = ireq.ifr6_addr.s6_addr32[3];
                p.iph.saddr = 0;
                p.iph.version = 4;
                p.iph.ihl = 5;
                p.iph.protocol = IPPROTO_IPV6;
                p.iph.ttl = 64;
                ifr.ifr_ifru.ifru_data = (__force void __user *)&p;

                if (ops->ndo_do_ioctl) {
                        mm_segment_t oldfs = get_fs();

                        set_fs(KERNEL_DS);
                        err = ops->ndo_do_ioctl(dev, &ifr, SIOCADDTUNNEL);
                        set_fs(oldfs);
                } else
                        err = -EOPNOTSUPP;

                if (err == 0) {
                        err = -ENOBUFS;
                        dev = __dev_get_by_name(net, p.name);
                        if (!dev)
                                goto err_exit;
                        err = dev_open(dev);
                }
        }
#endif

err_exit:
        rtnl_unlock();
        return err;
}

/*
 *      Manual configuration of address on an interface
 */
static int inet6_addr_add(struct net *net, int ifindex, const struct in6_addr *pfx,
                          unsigned int plen, __u8 ifa_flags, __u32 prefered_lft,
                          __u32 valid_lft)
{
        struct inet6_ifaddr *ifp;
        struct inet6_dev *idev;
        struct net_device *dev;
        int scope;
        u32 flags;
        clock_t expires;
        unsigned long timeout;

        ASSERT_RTNL();

        if (plen > 128)
                return -EINVAL;

        /* check the lifetime */
        if (!valid_lft || prefered_lft > valid_lft)
                return -EINVAL;

        dev = __dev_get_by_index(net, ifindex);
        if (!dev)
                return -ENODEV;

        idev = addrconf_add_dev(dev);
        if (IS_ERR(idev))
                return PTR_ERR(idev);

        scope = ipv6_addr_scope(pfx);

        timeout = addrconf_timeout_fixup(valid_lft, HZ);
        if (addrconf_finite_timeout(timeout)) {
                expires = jiffies_to_clock_t(timeout * HZ);
                valid_lft = timeout;
                flags = RTF_EXPIRES;
        } else {
                expires = 0;
                flags = 0;
                ifa_flags |= IFA_F_PERMANENT;
        }

        timeout = addrconf_timeout_fixup(prefered_lft, HZ);
        if (addrconf_finite_timeout(timeout)) {
                if (timeout == 0)
                        ifa_flags |= IFA_F_DEPRECATED;
                prefered_lft = timeout;
        }

        ifp = ipv6_add_addr(idev, pfx, plen, scope, ifa_flags);

        if (!IS_ERR(ifp)) {
                spin_lock_bh(&ifp->lock);
                ifp->valid_lft = valid_lft;
                ifp->prefered_lft = prefered_lft;
                ifp->tstamp = jiffies;
                spin_unlock_bh(&ifp->lock);

                addrconf_prefix_route(&ifp->addr, ifp->prefix_len, dev,
                                      expires, flags);
                /*
                 * Note that section 3.1 of RFC 4429 indicates
                 * that the Optimistic flag should not be set for
                 * manually configured addresses
                 */
                addrconf_dad_start(ifp);
                in6_ifa_put(ifp);
                addrconf_verify(0);
                return 0;
        }

        return PTR_ERR(ifp);
}

static int inet6_addr_del(struct net *net, int ifindex, const struct in6_addr *pfx,
                          unsigned int plen)
{
        struct inet6_ifaddr *ifp;
        struct inet6_dev *idev;
        struct net_device *dev;

        if (plen > 128)
                return -EINVAL;

        dev = __dev_get_by_index(net, ifindex);
        if (!dev)
                return -ENODEV;

        if ((idev = __in6_dev_get(dev)) == NULL)
                return -ENXIO;

        read_lock_bh(&idev->lock);
        list_for_each_entry(ifp, &idev->addr_list, if_list) {
                if (ifp->prefix_len == plen &&
                    ipv6_addr_equal(pfx, &ifp->addr)) {
                        in6_ifa_hold(ifp);
                        read_unlock_bh(&idev->lock);

                        ipv6_del_addr(ifp);

                        /* If the last address is deleted administratively,
                           disable IPv6 on this interface.
                         */
                        if (list_empty(&idev->addr_list))
                                addrconf_ifdown(idev->dev, 1);
                        return 0;
                }
        }
        read_unlock_bh(&idev->lock);
        return -EADDRNOTAVAIL;
}


int addrconf_add_ifaddr(struct net *net, void __user *arg)
{
        struct in6_ifreq ireq;
        int err;

        if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
                return -EPERM;

        if (copy_from_user(&ireq, arg, sizeof(struct in6_ifreq)))
                return -EFAULT;

        rtnl_lock();
        err = inet6_addr_add(net, ireq.ifr6_ifindex, &ireq.ifr6_addr,
                             ireq.ifr6_prefixlen, IFA_F_PERMANENT,
                             INFINITY_LIFE_TIME, INFINITY_LIFE_TIME);
        rtnl_unlock();
        return err;
}

int addrconf_del_ifaddr(struct net *net, void __user *arg)
{
        struct in6_ifreq ireq;
        int err;

        if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
                return -EPERM;

        if (copy_from_user(&ireq, arg, sizeof(struct in6_ifreq)))
                return -EFAULT;

        rtnl_lock();
        err = inet6_addr_del(net, ireq.ifr6_ifindex, &ireq.ifr6_addr,
                             ireq.ifr6_prefixlen);
        rtnl_unlock();
        return err;
}

static void add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
                     int plen, int scope)
{
        struct inet6_ifaddr *ifp;

        ifp = ipv6_add_addr(idev, addr, plen, scope, IFA_F_PERMANENT);
        if (!IS_ERR(ifp)) {
                spin_lock_bh(&ifp->lock);
                ifp->flags &= ~IFA_F_TENTATIVE;
                spin_unlock_bh(&ifp->lock);
                ipv6_ifa_notify(RTM_NEWADDR, ifp);
                in6_ifa_put(ifp);
        }
}

#if IS_ENABLED(CONFIG_IPV6_SIT)
static void sit_add_v4_addrs(struct inet6_dev *idev)
{
        struct in6_addr addr;
        struct net_device *dev;
        struct net *net = dev_net(idev->dev);
        int scope;

        ASSERT_RTNL();

        memset(&addr, 0, sizeof(struct in6_addr));
        memcpy(&addr.s6_addr32[3], idev->dev->dev_addr, 4);

        if (idev->dev->flags&IFF_POINTOPOINT) {
                addr.s6_addr32[0] = htonl(0xfe800000);
                scope = IFA_LINK;
        } else {
                scope = IPV6_ADDR_COMPATv4;
        }

        if (addr.s6_addr32[3]) {
                add_addr(idev, &addr, 128, scope);
                return;
        }

        for_each_netdev(net, dev) {
                struct in_device *in_dev = __in_dev_get_rtnl(dev);
                if (in_dev && (dev->flags & IFF_UP)) {
                        struct in_ifaddr *ifa;

                        int flag = scope;

                        for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {
                                int plen;

                                addr.s6_addr32[3] = ifa->ifa_local;

                                if (ifa->ifa_scope == RT_SCOPE_LINK)
                                        continue;
                                if (ifa->ifa_scope >= RT_SCOPE_HOST) {
                                        if (idev->dev->flags&IFF_POINTOPOINT)
                                                continue;
                                        flag |= IFA_HOST;
                                }
                                if (idev->dev->flags&IFF_POINTOPOINT)
                                        plen = 64;
                                else
                                        plen = 96;

                                add_addr(idev, &addr, plen, flag);
                        }
                }
        }
}
#endif

static void init_loopback(struct net_device *dev)
{
        struct inet6_dev  *idev;
        struct net_device *sp_dev;
        struct inet6_ifaddr *sp_ifa;
        struct rt6_info *sp_rt;

        /* ::1 */

        ASSERT_RTNL();

        if ((idev = ipv6_find_idev(dev)) == NULL) {
                pr_debug("%s: add_dev failed\n", __func__);
                return;
        }

        add_addr(idev, &in6addr_loopback, 128, IFA_HOST);

        /* Add routes to other interface's IPv6 addresses */
        for_each_netdev(dev_net(dev), sp_dev) {
                if (!strcmp(sp_dev->name, dev->name))
                        continue;

                idev = __in6_dev_get(sp_dev);
                if (!idev)
                        continue;

                read_lock_bh(&idev->lock);
                list_for_each_entry(sp_ifa, &idev->addr_list, if_list) {

                        if (sp_ifa->flags & (IFA_F_DADFAILED | IFA_F_TENTATIVE))
                                continue;

                        if (sp_ifa->rt)
                                continue;

                        sp_rt = addrconf_dst_alloc(idev, &sp_ifa->addr, 0);

                        /* Failure cases are ignored */
                        if (!IS_ERR(sp_rt)) {
                                sp_ifa->rt = sp_rt;
                                ip6_ins_rt(sp_rt);
                        }
                }
                read_unlock_bh(&idev->lock);
        }
}

static void addrconf_add_linklocal(struct inet6_dev *idev, const struct in6_addr *addr)
{
        struct inet6_ifaddr *ifp;
        u32 addr_flags = IFA_F_PERMANENT;

#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
        if (idev->cnf.optimistic_dad &&
            !dev_net(idev->dev)->ipv6.devconf_all->forwarding)
                addr_flags |= IFA_F_OPTIMISTIC;
#endif


        ifp = ipv6_add_addr(idev, addr, 64, IFA_LINK, addr_flags);
        if (!IS_ERR(ifp)) {
                addrconf_prefix_route(&ifp->addr, ifp->prefix_len, idev->dev, 0, 0);
                addrconf_dad_start(ifp);
                in6_ifa_put(ifp);
        }
}

static void addrconf_dev_config(struct net_device *dev)
{
        struct in6_addr addr;
        struct inet6_dev *idev;

        ASSERT_RTNL();

        if ((dev->type != ARPHRD_ETHER) &&
            (dev->type != ARPHRD_FDDI) &&
            (dev->type != ARPHRD_ARCNET) &&
            (dev->type != ARPHRD_INFINIBAND) &&
            (dev->type != ARPHRD_IEEE802154) &&
            (dev->type != ARPHRD_IEEE1394)) {
                /* Alas, we support only Ethernet autoconfiguration. */
                return;
        }

        idev = addrconf_add_dev(dev);
        if (IS_ERR(idev))
                return;

        memset(&addr, 0, sizeof(struct in6_addr));
        addr.s6_addr32[0] = htonl(0xFE800000);

        if (ipv6_generate_eui64(addr.s6_addr + 8, dev) == 0)
                addrconf_add_linklocal(idev, &addr);
}

#if IS_ENABLED(CONFIG_IPV6_SIT)
static void addrconf_sit_config(struct net_device *dev)
{
        struct inet6_dev *idev;

        ASSERT_RTNL();

        /*
         * Configure the tunnel with one of our IPv4
         * addresses... we should configure all of
         * our v4 addrs in the tunnel
         */

        if ((idev = ipv6_find_idev(dev)) == NULL) {
                pr_debug("%s: add_dev failed\n", __func__);
                return;
        }

        if (dev->priv_flags & IFF_ISATAP) {
                struct in6_addr addr;

                ipv6_addr_set(&addr,  htonl(0xFE800000), 0, 0, 0);
                addrconf_prefix_route(&addr, 64, dev, 0, 0);
                if (!ipv6_generate_eui64(addr.s6_addr + 8, dev))
                        addrconf_add_linklocal(idev, &addr);
                return;
        }

        sit_add_v4_addrs(idev);

        if (dev->flags&IFF_POINTOPOINT)
                addrconf_add_mroute(dev);
        else
                sit_route_add(dev);
}
#endif

#if IS_ENABLED(CONFIG_NET_IPGRE)
static void addrconf_gre_config(struct net_device *dev)
{
        struct inet6_dev *idev;
        struct in6_addr addr;

        pr_info("%s(%s)\n", __func__, dev->name);

        ASSERT_RTNL();

        if ((idev = ipv6_find_idev(dev)) == NULL) {
                pr_debug("%s: add_dev failed\n", __func__);
                return;
        }

        ipv6_addr_set(&addr,  htonl(0xFE800000), 0, 0, 0);
        addrconf_prefix_route(&addr, 64, dev, 0, 0);

        if (!ipv6_generate_eui64(addr.s6_addr + 8, dev))
                addrconf_add_linklocal(idev, &addr);
}
#endif

static inline int
ipv6_inherit_linklocal(struct inet6_dev *idev, struct net_device *link_dev)
{
        struct in6_addr lladdr;

        if (!ipv6_get_lladdr(link_dev, &lladdr, IFA_F_TENTATIVE)) {
                addrconf_add_linklocal(idev, &lladdr);
                return 0;
        }
        return -1;
}

static void ip6_tnl_add_linklocal(struct inet6_dev *idev)
{
        struct net_device *link_dev;
        struct net *net = dev_net(idev->dev);

        /* first try to inherit the link-local address from the link device */
        if (idev->dev->iflink &&
            (link_dev = __dev_get_by_index(net, idev->dev->iflink))) {
                if (!ipv6_inherit_linklocal(idev, link_dev))
                        return;
        }
        /* then try to inherit it from any device */
        for_each_netdev(net, link_dev) {
                if (!ipv6_inherit_linklocal(idev, link_dev))
                        return;
        }
        pr_debug("init ip6-ip6: add_linklocal failed\n");
}

/*
 * Autoconfigure tunnel with a link-local address so routing protocols,
 * DHCPv6, MLD etc. can be run over the virtual link
 */

static void addrconf_ip6_tnl_config(struct net_device *dev)
{
        struct inet6_dev *idev;

        ASSERT_RTNL();

        idev = addrconf_add_dev(dev);
        if (IS_ERR(idev)) {
                pr_debug("init ip6-ip6: add_dev failed\n");
                return;
        }
        ip6_tnl_add_linklocal(idev);
}

static int addrconf_notify(struct notifier_block *this, unsigned long event,
                           void *data)
{
        struct net_device *dev = (struct net_device *) data;
        struct inet6_dev *idev = __in6_dev_get(dev);
        int run_pending = 0;
        int err;

        switch (event) {
        case NETDEV_REGISTER:
                if (!idev && dev->mtu >= IPV6_MIN_MTU) {
                        idev = ipv6_add_dev(dev);
                        if (!idev)
                                return notifier_from_errno(-ENOMEM);
                }
                break;

        case NETDEV_UP:
        case NETDEV_CHANGE:
                if (dev->flags & IFF_SLAVE)
                        break;

                if (event == NETDEV_UP) {
                        if (!addrconf_qdisc_ok(dev)) {
                                /* device is not ready yet. */
                                pr_info("ADDRCONF(NETDEV_UP): %s: link is not ready\n",
                                        dev->name);
                                break;
                        }

                        if (!idev && dev->mtu >= IPV6_MIN_MTU)
                                idev = ipv6_add_dev(dev);

                        if (idev) {
                                idev->if_flags |= IF_READY;
                                run_pending = 1;
                        }
                } else {
                        if (!addrconf_qdisc_ok(dev)) {
                                /* device is still not ready. */
                                break;
                        }

                        if (idev) {
                                if (idev->if_flags & IF_READY)
                                        /* device is already configured. */
                                        break;
                                idev->if_flags |= IF_READY;
                        }

                        pr_info("ADDRCONF(NETDEV_CHANGE): %s: link becomes ready\n",
                                dev->name);

                        run_pending = 1;
                }

                switch (dev->type) {
#if IS_ENABLED(CONFIG_IPV6_SIT)
                case ARPHRD_SIT:
                        addrconf_sit_config(dev);
                        break;
#endif
#if IS_ENABLED(CONFIG_NET_IPGRE)
                case ARPHRD_IPGRE:
                        addrconf_gre_config(dev);
                        break;
#endif
                case ARPHRD_TUNNEL6:
                        addrconf_ip6_tnl_config(dev);
                        break;
                case ARPHRD_LOOPBACK:
                        init_loopback(dev);
                        break;

                default:
                        addrconf_dev_config(dev);
                        break;
                }

                if (idev) {
                        if (run_pending)
                                addrconf_dad_run(idev);

                        /*
                         * If the MTU changed during the interface down,
                         * when the interface up, the changed MTU must be
                         * reflected in the idev as well as routers.
                         */
                        if (idev->cnf.mtu6 != dev->mtu &&
                            dev->mtu >= IPV6_MIN_MTU) {
                                rt6_mtu_change(dev, dev->mtu);
                                idev->cnf.mtu6 = dev->mtu;
                        }
                        idev->tstamp = jiffies;
                        inet6_ifinfo_notify(RTM_NEWLINK, idev);

                        /*
                         * If the changed mtu during down is lower than
                         * IPV6_MIN_MTU stop IPv6 on this interface.
                         */
                        if (dev->mtu < IPV6_MIN_MTU)
                                addrconf_ifdown(dev, 1);
                }
                break;

        case NETDEV_CHANGEMTU:
                if (idev && dev->mtu >= IPV6_MIN_MTU) {
                        rt6_mtu_change(dev, dev->mtu);
                        idev->cnf.mtu6 = dev->mtu;
                        break;
                }

                if (!idev && dev->mtu >= IPV6_MIN_MTU) {
                        idev = ipv6_add_dev(dev);
                        if (idev)
                                break;
                }

                /*
                 * MTU falled under IPV6_MIN_MTU.
                 * Stop IPv6 on this interface.
                 */

        case NETDEV_DOWN:
        case NETDEV_UNREGISTER:
                /*
                 *      Remove all addresses from this interface.
                 */
                addrconf_ifdown(dev, event != NETDEV_DOWN);
                break;

        case NETDEV_CHANGENAME:
                if (idev) {
                        snmp6_unregister_dev(idev);
                        addrconf_sysctl_unregister(idev);
                        addrconf_sysctl_register(idev);
                        err = snmp6_register_dev(idev);
                        if (err)
                                return notifier_from_errno(err);
                }
                break;

        case NETDEV_PRE_TYPE_CHANGE:
        case NETDEV_POST_TYPE_CHANGE:
                addrconf_type_change(dev, event);
                break;
        }

        return NOTIFY_OK;
}

/*
 *      addrconf module should be notified of a device going up
 */
static struct notifier_block ipv6_dev_notf = {
        .notifier_call = addrconf_notify,
};

static void addrconf_type_change(struct net_device *dev, unsigned long event)
{
        struct inet6_dev *idev;
        ASSERT_RTNL();

        idev = __in6_dev_get(dev);

        if (event == NETDEV_POST_TYPE_CHANGE)
                ipv6_mc_remap(idev);
        else if (event == NETDEV_PRE_TYPE_CHANGE)
                ipv6_mc_unmap(idev);
}

static int addrconf_ifdown(struct net_device *dev, int how)
{
        struct net *net = dev_net(dev);
        struct inet6_dev *idev;
        struct inet6_ifaddr *ifa;
        int state, i;

        ASSERT_RTNL();

        rt6_ifdown(net, dev);
        neigh_ifdown(&nd_tbl, dev);

        idev = __in6_dev_get(dev);
        if (idev == NULL)
                return -ENODEV;

        /*
         * Step 1: remove reference to ipv6 device from parent device.
         *         Do not dev_put!
         */
        if (how) {
                idev->dead = 1;

                /* protected by rtnl_lock */
                RCU_INIT_POINTER(dev->ip6_ptr, NULL);

                /* Step 1.5: remove snmp6 entry */
                snmp6_unregister_dev(idev);

        }

        /* Step 2: clear hash table */
        for (i = 0; i < IN6_ADDR_HSIZE; i++) {
                struct hlist_head *h = &inet6_addr_lst[i];

                spin_lock_bh(&addrconf_hash_lock);
        restart:
                hlist_for_each_entry_rcu(ifa, h, addr_lst) {
                        if (ifa->idev == idev) {
                                hlist_del_init_rcu(&ifa->addr_lst);
                                addrconf_del_timer(ifa);
                                goto restart;
                        }
                }
                spin_unlock_bh(&addrconf_hash_lock);
        }

        write_lock_bh(&idev->lock);

        /* Step 2: clear flags for stateless addrconf */
        if (!how)
                idev->if_flags &= ~(IF_RS_SENT|IF_RA_RCVD|IF_READY);

#ifdef CONFIG_IPV6_PRIVACY
        if (how && del_timer(&idev->regen_timer))
                in6_dev_put(idev);

        /* Step 3: clear tempaddr list */
        while (!list_empty(&idev->tempaddr_list)) {
                ifa = list_first_entry(&idev->tempaddr_list,
                                       struct inet6_ifaddr, tmp_list);
                list_del(&ifa->tmp_list);
                write_unlock_bh(&idev->lock);
                spin_lock_bh(&ifa->lock);

                if (ifa->ifpub) {
                        in6_ifa_put(ifa->ifpub);
                        ifa->ifpub = NULL;
                }
                spin_unlock_bh(&ifa->lock);
                in6_ifa_put(ifa);
                write_lock_bh(&idev->lock);
        }
#endif

        while (!list_empty(&idev->addr_list)) {
                ifa = list_first_entry(&idev->addr_list,
                                       struct inet6_ifaddr, if_list);
                addrconf_del_timer(ifa);

                list_del(&ifa->if_list);

                write_unlock_bh(&idev->lock);

                spin_lock_bh(&ifa->state_lock);
                state = ifa->state;
                ifa->state = INET6_IFADDR_STATE_DEAD;
                spin_unlock_bh(&ifa->state_lock);

                if (state != INET6_IFADDR_STATE_DEAD) {
                        __ipv6_ifa_notify(RTM_DELADDR, ifa);
                        inet6addr_notifier_call_chain(NETDEV_DOWN, ifa);
                }
                in6_ifa_put(ifa);

                write_lock_bh(&idev->lock);
        }

        write_unlock_bh(&idev->lock);

        /* Step 5: Discard multicast list */
        if (how)
                ipv6_mc_destroy_dev(idev);
        else
                ipv6_mc_down(idev);

        idev->tstamp = jiffies;

        /* Last: Shot the device (if unregistered) */
        if (how) {
                addrconf_sysctl_unregister(idev);
                neigh_parms_release(&nd_tbl, idev->nd_parms);
                neigh_ifdown(&nd_tbl, dev);
                in6_dev_put(idev);
        }
        return 0;
}

static void addrconf_rs_timer(unsigned long data)
{
        struct inet6_ifaddr *ifp = (struct inet6_ifaddr *) data;
        struct inet6_dev *idev = ifp->idev;

        read_lock(&idev->lock);
        if (idev->dead || !(idev->if_flags & IF_READY))
                goto out;

        if (!ipv6_accept_ra(idev))
                goto out;

        /* Announcement received after solicitation was sent */
        if (idev->if_flags & IF_RA_RCVD)
                goto out;

        spin_lock(&ifp->lock);
        if (ifp->probes++ < idev->cnf.rtr_solicits) {
                /* The wait after the last probe can be shorter */
                addrconf_mod_timer(ifp, AC_RS,
                                   (ifp->probes == idev->cnf.rtr_solicits) ?
                                   idev->cnf.rtr_solicit_delay :
                                   idev->cnf.rtr_solicit_interval);
                spin_unlock(&ifp->lock);

                ndisc_send_rs(idev->dev, &ifp->addr, &in6addr_linklocal_allrouters);
        } else {
                spin_unlock(&ifp->lock);
                /*
                 * Note: we do not support deprecated "all on-link"
                 * assumption any longer.
                 */
                pr_debug("%s: no IPv6 routers present\n", idev->dev->name);
        }

out:
        read_unlock(&idev->lock);
        in6_ifa_put(ifp);
}

/*
 *      Duplicate Address Detection
 */
static void addrconf_dad_kick(struct inet6_ifaddr *ifp)
{
        unsigned long rand_num;
        struct inet6_dev *idev = ifp->idev;

        if (ifp->flags & IFA_F_OPTIMISTIC)
                rand_num = 0;
        else
                rand_num = net_random() % (idev->cnf.rtr_solicit_delay ? : 1);

        ifp->probes = idev->cnf.dad_transmits;
        addrconf_mod_timer(ifp, AC_DAD, rand_num);
}

static void addrconf_dad_start(struct inet6_ifaddr *ifp)
{
        struct inet6_dev *idev = ifp->idev;
        struct net_device *dev = idev->dev;

        addrconf_join_solict(dev, &ifp->addr);

        net_srandom(ifp->addr.s6_addr32[3]);

        read_lock_bh(&idev->lock);
        spin_lock(&ifp->lock);
        if (ifp->state == INET6_IFADDR_STATE_DEAD)
                goto out;

        if (dev->flags&(IFF_NOARP|IFF_LOOPBACK) ||
            idev->cnf.accept_dad < 1 ||
            !(ifp->flags&IFA_F_TENTATIVE) ||
            ifp->flags & IFA_F_NODAD) {
                ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC|IFA_F_DADFAILED);
                spin_unlock(&ifp->lock);
                read_unlock_bh(&idev->lock);

                addrconf_dad_completed(ifp);
                return;
        }

        if (!(idev->if_flags & IF_READY)) {
                spin_unlock(&ifp->lock);
                read_unlock_bh(&idev->lock);
                /*
                 * If the device is not ready:
                 * - keep it tentative if it is a permanent address.
                 * - otherwise, kill it.
                 */
                in6_ifa_hold(ifp);
                addrconf_dad_stop(ifp, 0);
                return;
        }

        /*
         * Optimistic nodes can start receiving
         * Frames right away
         */
        if (ifp->flags & IFA_F_OPTIMISTIC)
                ip6_ins_rt(ifp->rt);

        addrconf_dad_kick(ifp);
out:
        spin_unlock(&ifp->lock);
        read_unlock_bh(&idev->lock);
}

static void addrconf_dad_timer(unsigned long data)
{
        struct inet6_ifaddr *ifp = (struct inet6_ifaddr *) data;
        struct inet6_dev *idev = ifp->idev;
        struct in6_addr mcaddr;

        if (!ifp->probes && addrconf_dad_end(ifp))
                goto out;

        read_lock(&idev->lock);
        if (idev->dead || !(idev->if_flags & IF_READY)) {
                read_unlock(&idev->lock);
                goto out;
        }

        spin_lock(&ifp->lock);
        if (ifp->state == INET6_IFADDR_STATE_DEAD) {
                spin_unlock(&ifp->lock);
                read_unlock(&idev->lock);
                goto out;
        }

        if (ifp->probes == 0) {
                /*
                 * DAD was successful
                 */

                ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC|IFA_F_DADFAILED);
                spin_unlock(&ifp->lock);
                read_unlock(&idev->lock);

                addrconf_dad_completed(ifp);

                goto out;
        }

        ifp->probes--;
        addrconf_mod_timer(ifp, AC_DAD, ifp->idev->nd_parms->retrans_time);
        spin_unlock(&ifp->lock);
        read_unlock(&idev->lock);

        /* send a neighbour solicitation for our addr */
        addrconf_addr_solict_mult(&ifp->addr, &mcaddr);
        ndisc_send_ns(ifp->idev->dev, NULL, &ifp->addr, &mcaddr, &in6addr_any);
out:
        in6_ifa_put(ifp);
}

static void addrconf_dad_completed(struct inet6_ifaddr *ifp)
{
        struct net_device *dev = ifp->idev->dev;

        /*
         *      Configure the address for reception. Now it is valid.
         */

        ipv6_ifa_notify(RTM_NEWADDR, ifp);

        /* If added prefix is link local and we are prepared to process
           router advertisements, start sending router solicitations.
         */

        if (ipv6_accept_ra(ifp->idev) &&
            ifp->idev->cnf.rtr_solicits > 0 &&
            (dev->flags&IFF_LOOPBACK) == 0 &&
            (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)) {
                /*
                 *      If a host as already performed a random delay
                 *      [...] as part of DAD [...] there is no need
                 *      to delay again before sending the first RS
                 */
                ndisc_send_rs(ifp->idev->dev, &ifp->addr, &in6addr_linklocal_allrouters);

                spin_lock_bh(&ifp->lock);
                ifp->probes = 1;
                ifp->idev->if_flags |= IF_RS_SENT;
                addrconf_mod_timer(ifp, AC_RS, ifp->idev->cnf.rtr_solicit_interval);
                spin_unlock_bh(&ifp->lock);
        }
}

static void addrconf_dad_run(struct inet6_dev *idev)
{
        struct inet6_ifaddr *ifp;

        read_lock_bh(&idev->lock);
        list_for_each_entry(ifp, &idev->addr_list, if_list) {
                spin_lock(&ifp->lock);
                if (ifp->flags & IFA_F_TENTATIVE &&
                    ifp->state == INET6_IFADDR_STATE_DAD)
                        addrconf_dad_kick(ifp);
                spin_unlock(&ifp->lock);
        }
        read_unlock_bh(&idev->lock);
}

#ifdef CONFIG_PROC_FS
struct if6_iter_state {
        struct seq_net_private p;
        int bucket;
        int offset;
};

static struct inet6_ifaddr *if6_get_first(struct seq_file *seq, loff_t pos)
{
        struct inet6_ifaddr *ifa = NULL;
        struct if6_iter_state *state = seq->private;
        struct net *net = seq_file_net(seq);
        int p = 0;

        /* initial bucket if pos is 0 */
        if (pos == 0) {
                state->bucket = 0;
                state->offset = 0;
        }

        for (; state->bucket < IN6_ADDR_HSIZE; ++state->bucket) {
                hlist_for_each_entry_rcu_bh(ifa, &inet6_addr_lst[state->bucket],
                                         addr_lst) {
                        if (!net_eq(dev_net(ifa->idev->dev), net))
                                continue;
                        /* sync with offset */
                        if (p < state->offset) {
                                p++;
                                continue;
                        }
                        state->offset++;
                        return ifa;
                }

                /* prepare for next bucket */
                state->offset = 0;
                p = 0;
        }
        return NULL;
}

static struct inet6_ifaddr *if6_get_next(struct seq_file *seq,
                                         struct inet6_ifaddr *ifa)
{
        struct if6_iter_state *state = seq->private;
        struct net *net = seq_file_net(seq);

        hlist_for_each_entry_continue_rcu_bh(ifa, addr_lst) {
                if (!net_eq(dev_net(ifa->idev->dev), net))
                        continue;
                state->offset++;
                return ifa;
        }

        while (++state->bucket < IN6_ADDR_HSIZE) {
                state->offset = 0;
                hlist_for_each_entry_rcu_bh(ifa,
                                     &inet6_addr_lst[state->bucket], addr_lst) {
                        if (!net_eq(dev_net(ifa->idev->dev), net))
                                continue;
                        state->offset++;
                        return ifa;
                }
        }

        return NULL;
}

static void *if6_seq_start(struct seq_file *seq, loff_t *pos)
        __acquires(rcu_bh)
{
        rcu_read_lock_bh();
        return if6_get_first(seq, *pos);
}

static void *if6_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
        struct inet6_ifaddr *ifa;

        ifa = if6_get_next(seq, v);
        ++*pos;
        return ifa;
}

static void if6_seq_stop(struct seq_file *seq, void *v)
        __releases(rcu_bh)
{
        rcu_read_unlock_bh();
}

static int if6_seq_show(struct seq_file *seq, void *v)
{
        struct inet6_ifaddr *ifp = (struct inet6_ifaddr *)v;
        seq_printf(seq, "%pi6 %02x %02x %02x %02x %8s\n",
                   &ifp->addr,
                   ifp->idev->dev->ifindex,
                   ifp->prefix_len,
                   ifp->scope,
                   ifp->flags,
                   ifp->idev->dev->name);
        return 0;
}

static const struct seq_operations if6_seq_ops = {
        .start  = if6_seq_start,
        .next   = if6_seq_next,
        .show   = if6_seq_show,
        .stop   = if6_seq_stop,
};

static int if6_seq_open(struct inode *inode, struct file *file)
{
        return seq_open_net(inode, file, &if6_seq_ops,
                            sizeof(struct if6_iter_state));
}

static const struct file_operations if6_fops = {
        .owner          = THIS_MODULE,
        .open           = if6_seq_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = seq_release_net,
};

static int __net_init if6_proc_net_init(struct net *net)
{
        if (!proc_create("if_inet6", S_IRUGO, net->proc_net, &if6_fops))
                return -ENOMEM;
        return 0;
}

static void __net_exit if6_proc_net_exit(struct net *net)
{
        remove_proc_entry("if_inet6", net->proc_net);
}

static struct pernet_operations if6_proc_net_ops = {
       .init = if6_proc_net_init,
       .exit = if6_proc_net_exit,
};

int __init if6_proc_init(void)
{
        return register_pernet_subsys(&if6_proc_net_ops);
}

void if6_proc_exit(void)
{
        unregister_pernet_subsys(&if6_proc_net_ops);
}
#endif  /* CONFIG_PROC_FS */

#if IS_ENABLED(CONFIG_IPV6_MIP6)
/* Check if address is a home address configured on any interface. */
int ipv6_chk_home_addr(struct net *net, const struct in6_addr *addr)
{
        int ret = 0;
        struct inet6_ifaddr *ifp = NULL;
        unsigned int hash = inet6_addr_hash(addr);

        rcu_read_lock_bh();
        hlist_for_each_entry_rcu_bh(ifp, &inet6_addr_lst[hash], addr_lst) {
                if (!net_eq(dev_net(ifp->idev->dev), net))
                        continue;
                if (ipv6_addr_equal(&ifp->addr, addr) &&
                    (ifp->flags & IFA_F_HOMEADDRESS)) {
                        ret = 1;
                        break;
                }
        }
        rcu_read_unlock_bh();
        return ret;
}
#endif

/*
 *      Periodic address status verification
 */

static void addrconf_verify(unsigned long foo)
{
        unsigned long now, next, next_sec, next_sched;
        struct inet6_ifaddr *ifp;
        int i;

        rcu_read_lock_bh();
        spin_lock(&addrconf_verify_lock);
        now = jiffies;
        next = round_jiffies_up(now + ADDR_CHECK_FREQUENCY);

        del_timer(&addr_chk_timer);

        for (i = 0; i < IN6_ADDR_HSIZE; i++) {
restart:
                hlist_for_each_entry_rcu_bh(ifp,
                                         &inet6_addr_lst[i], addr_lst) {
                        unsigned long age;

                        if (ifp->flags & IFA_F_PERMANENT)
                                continue;

                        spin_lock(&ifp->lock);
                        /* We try to batch several events at once. */
                        age = (now - ifp->tstamp + ADDRCONF_TIMER_FUZZ_MINUS) / HZ;

                        if (ifp->valid_lft != INFINITY_LIFE_TIME &&
                            age >= ifp->valid_lft) {
                                spin_unlock(&ifp->lock);
                                in6_ifa_hold(ifp);
                                ipv6_del_addr(ifp);
                                goto restart;
                        } else if (ifp->prefered_lft == INFINITY_LIFE_TIME) {
                                spin_unlock(&ifp->lock);
                                continue;
                        } else if (age >= ifp->prefered_lft) {
                                /* jiffies - ifp->tstamp > age >= ifp->prefered_lft */
                                int deprecate = 0;

                                if (!(ifp->flags&IFA_F_DEPRECATED)) {
                                        deprecate = 1;
                                        ifp->flags |= IFA_F_DEPRECATED;
                                }

                                if (time_before(ifp->tstamp + ifp->valid_lft * HZ, next))
                                        next = ifp->tstamp + ifp->valid_lft * HZ;

                                spin_unlock(&ifp->lock);

                                if (deprecate) {
                                        in6_ifa_hold(ifp);

                                        ipv6_ifa_notify(0, ifp);
                                        in6_ifa_put(ifp);
                                        goto restart;
                                }
#ifdef CONFIG_IPV6_PRIVACY
                        } else if ((ifp->flags&IFA_F_TEMPORARY) &&
                                   !(ifp->flags&IFA_F_TENTATIVE)) {
                                unsigned long regen_advance = ifp->idev->cnf.regen_max_retry *
                                        ifp->idev->cnf.dad_transmits *
                                        ifp->idev->nd_parms->retrans_time / HZ;

                                if (age >= ifp->prefered_lft - regen_advance) {
                                        struct inet6_ifaddr *ifpub = ifp->ifpub;
                                        if (time_before(ifp->tstamp + ifp->prefered_lft * HZ, next))
                                                next = ifp->tstamp + ifp->prefered_lft * HZ;
                                        if (!ifp->regen_count && ifpub) {
                                                ifp->regen_count++;
                                                in6_ifa_hold(ifp);
                                                in6_ifa_hold(ifpub);
                                                spin_unlock(&ifp->lock);

                                                spin_lock(&ifpub->lock);
                                                ifpub->regen_count = 0;
                                                spin_unlock(&ifpub->lock);
                                                ipv6_create_tempaddr(ifpub, ifp);
                                                in6_ifa_put(ifpub);
                                                in6_ifa_put(ifp);
                                                goto restart;
                                        }
                                } else if (time_before(ifp->tstamp + ifp->prefered_lft * HZ - regen_advance * HZ, next))
                                        next = ifp->tstamp + ifp->prefered_lft * HZ - regen_advance * HZ;
                                spin_unlock(&ifp->lock);
#endif
                        } else {
                                /* ifp->prefered_lft <= ifp->valid_lft */
                                if (time_before(ifp->tstamp + ifp->prefered_lft * HZ, next))
                                        next = ifp->tstamp + ifp->prefered_lft * HZ;
                                spin_unlock(&ifp->lock);
                        }
                }
        }

        next_sec = round_jiffies_up(next);
        next_sched = next;

        /* If rounded timeout is accurate enough, accept it. */
        if (time_before(next_sec, next + ADDRCONF_TIMER_FUZZ))
                next_sched = next_sec;

        /* And minimum interval is ADDRCONF_TIMER_FUZZ_MAX. */
        if (time_before(next_sched, jiffies + ADDRCONF_TIMER_FUZZ_MAX))
                next_sched = jiffies + ADDRCONF_TIMER_FUZZ_MAX;

        ADBG((KERN_DEBUG "now = %lu, schedule = %lu, rounded schedule = %lu => %lu\n",
              now, next, next_sec, next_sched));

        addr_chk_timer.expires = next_sched;
        add_timer(&addr_chk_timer);
        spin_unlock(&addrconf_verify_lock);
        rcu_read_unlock_bh();
}

static struct in6_addr *extract_addr(struct nlattr *addr, struct nlattr *local)
{
        struct in6_addr *pfx = NULL;

        if (addr)
                pfx = nla_data(addr);

        if (local) {
                if (pfx && nla_memcmp(local, pfx, sizeof(*pfx)))
                        pfx = NULL;
                else
                        pfx = nla_data(local);
        }

        return pfx;
}

static const struct nla_policy ifa_ipv6_policy[IFA_MAX+1] = {
        [IFA_ADDRESS]           = { .len = sizeof(struct in6_addr) },
        [IFA_LOCAL]             = { .len = sizeof(struct in6_addr) },
        [IFA_CACHEINFO]         = { .len = sizeof(struct ifa_cacheinfo) },
};

static int
inet6_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh)
{
        struct net *net = sock_net(skb->sk);
        struct ifaddrmsg *ifm;
        struct nlattr *tb[IFA_MAX+1];
        struct in6_addr *pfx;
        int err;

        err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_ipv6_policy);
        if (err < 0)
                return err;

        ifm = nlmsg_data(nlh);
        pfx = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL]);
        if (pfx == NULL)
                return -EINVAL;

        return inet6_addr_del(net, ifm->ifa_index, pfx, ifm->ifa_prefixlen);
}

static int inet6_addr_modify(struct inet6_ifaddr *ifp, u8 ifa_flags,
                             u32 prefered_lft, u32 valid_lft)
{
        u32 flags;
        clock_t expires;
        unsigned long timeout;

        if (!valid_lft || (prefered_lft > valid_lft))
                return -EINVAL;

        timeout = addrconf_timeout_fixup(valid_lft, HZ);
        if (addrconf_finite_timeout(timeout)) {
                expires = jiffies_to_clock_t(timeout * HZ);
                valid_lft = timeout;
                flags = RTF_EXPIRES;
        } else {
                expires = 0;
                flags = 0;
                ifa_flags |= IFA_F_PERMANENT;
        }

        timeout = addrconf_timeout_fixup(prefered_lft, HZ);
        if (addrconf_finite_timeout(timeout)) {
                if (timeout == 0)
                        ifa_flags |= IFA_F_DEPRECATED;
                prefered_lft = timeout;
        }

        spin_lock_bh(&ifp->lock);
        ifp->flags = (ifp->flags & ~(IFA_F_DEPRECATED | IFA_F_PERMANENT | IFA_F_NODAD | IFA_F_HOMEADDRESS)) | ifa_flags;
        ifp->tstamp = jiffies;
        ifp->valid_lft = valid_lft;
        ifp->prefered_lft = prefered_lft;

        spin_unlock_bh(&ifp->lock);
        if (!(ifp->flags&IFA_F_TENTATIVE))
                ipv6_ifa_notify(0, ifp);

        addrconf_prefix_route(&ifp->addr, ifp->prefix_len, ifp->idev->dev,
                              expires, flags);
        addrconf_verify(0);

        return 0;
}

static int
inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh)
{
        struct net *net = sock_net(skb->sk);
        struct ifaddrmsg *ifm;
        struct nlattr *tb[IFA_MAX+1];
        struct in6_addr *pfx;
        struct inet6_ifaddr *ifa;
        struct net_device *dev;
        u32 valid_lft = INFINITY_LIFE_TIME, preferred_lft = INFINITY_LIFE_TIME;
        u8 ifa_flags;
        int err;

        err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_ipv6_policy);
        if (err < 0)
                return err;

        ifm = nlmsg_data(nlh);
        pfx = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL]);
        if (pfx == NULL)
                return -EINVAL;

        if (tb[IFA_CACHEINFO]) {
                struct ifa_cacheinfo *ci;

                ci = nla_data(tb[IFA_CACHEINFO]);
                valid_lft = ci->ifa_valid;
                preferred_lft = ci->ifa_prefered;
        } else {
                preferred_lft = INFINITY_LIFE_TIME;
                valid_lft = INFINITY_LIFE_TIME;
        }

        dev =  __dev_get_by_index(net, ifm->ifa_index);
        if (dev == NULL)
                return -ENODEV;

        /* We ignore other flags so far. */
        ifa_flags = ifm->ifa_flags & (IFA_F_NODAD | IFA_F_HOMEADDRESS);

        ifa = ipv6_get_ifaddr(net, pfx, dev, 1);
        if (ifa == NULL) {
                /*
                 * It would be best to check for !NLM_F_CREATE here but
                 * userspace alreay relies on not having to provide this.
                 */
                return inet6_addr_add(net, ifm->ifa_index, pfx,
                                      ifm->ifa_prefixlen, ifa_flags,
                                      preferred_lft, valid_lft);
        }

        if (nlh->nlmsg_flags & NLM_F_EXCL ||
            !(nlh->nlmsg_flags & NLM_F_REPLACE))
                err = -EEXIST;
        else
                err = inet6_addr_modify(ifa, ifa_flags, preferred_lft, valid_lft);

        in6_ifa_put(ifa);

        return err;
}

static void put_ifaddrmsg(struct nlmsghdr *nlh, u8 prefixlen, u8 flags,
                          u8 scope, int ifindex)
{
        struct ifaddrmsg *ifm;

        ifm = nlmsg_data(nlh);
        ifm->ifa_family = AF_INET6;
        ifm->ifa_prefixlen = prefixlen;
        ifm->ifa_flags = flags;
        ifm->ifa_scope = scope;
        ifm->ifa_index = ifindex;
}

static int put_cacheinfo(struct sk_buff *skb, unsigned long cstamp,
                         unsigned long tstamp, u32 preferred, u32 valid)
{
        struct ifa_cacheinfo ci;

        ci.cstamp = cstamp_delta(cstamp);
        ci.tstamp = cstamp_delta(tstamp);
        ci.ifa_prefered = preferred;
        ci.ifa_valid = valid;

        return nla_put(skb, IFA_CACHEINFO, sizeof(ci), &ci);
}

static inline int rt_scope(int ifa_scope)
{
        if (ifa_scope & IFA_HOST)
                return RT_SCOPE_HOST;
        else if (ifa_scope & IFA_LINK)
                return RT_SCOPE_LINK;
        else if (ifa_scope & IFA_SITE)
                return RT_SCOPE_SITE;
        else
                return RT_SCOPE_UNIVERSE;
}

static inline int inet6_ifaddr_msgsize(void)
{
        return NLMSG_ALIGN(sizeof(struct ifaddrmsg))
               + nla_total_size(16) /* IFA_ADDRESS */
               + nla_total_size(sizeof(struct ifa_cacheinfo));
}

static int inet6_fill_ifaddr(struct sk_buff *skb, struct inet6_ifaddr *ifa,
                             u32 portid, u32 seq, int event, unsigned int flags)
{
        struct nlmsghdr  *nlh;
        u32 preferred, valid;

        nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct ifaddrmsg), flags);
        if (nlh == NULL)
                return -EMSGSIZE;

        put_ifaddrmsg(nlh, ifa->prefix_len, ifa->flags, rt_scope(ifa->scope),
                      ifa->idev->dev->ifindex);

        if (!(ifa->flags&IFA_F_PERMANENT)) {
                preferred = ifa->prefered_lft;
                valid = ifa->valid_lft;
                if (preferred != INFINITY_LIFE_TIME) {
                        long tval = (jiffies - ifa->tstamp)/HZ;
                        if (preferred > tval)
                                preferred -= tval;
                        else
                                preferred = 0;
                        if (valid != INFINITY_LIFE_TIME) {
                                if (valid > tval)
                                        valid -= tval;
                                else
                                        valid = 0;
                        }
                }
        } else {
                preferred = INFINITY_LIFE_TIME;
                valid = INFINITY_LIFE_TIME;
        }

        if (nla_put(skb, IFA_ADDRESS, 16, &ifa->addr) < 0 ||
            put_cacheinfo(skb, ifa->cstamp, ifa->tstamp, preferred, valid) < 0) {
                nlmsg_cancel(skb, nlh);
                return -EMSGSIZE;
        }

        return nlmsg_end(skb, nlh);
}

static int inet6_fill_ifmcaddr(struct sk_buff *skb, struct ifmcaddr6 *ifmca,
                                u32 portid, u32 seq, int event, u16 flags)
{
        struct nlmsghdr  *nlh;
        u8 scope = RT_SCOPE_UNIVERSE;
        int ifindex = ifmca->idev->dev->ifindex;

        if (ipv6_addr_scope(&ifmca->mca_addr) & IFA_SITE)
                scope = RT_SCOPE_SITE;

        nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct ifaddrmsg), flags);
        if (nlh == NULL)
                return -EMSGSIZE;

        put_ifaddrmsg(nlh, 128, IFA_F_PERMANENT, scope, ifindex);
        if (nla_put(skb, IFA_MULTICAST, 16, &ifmca->mca_addr) < 0 ||
            put_cacheinfo(skb, ifmca->mca_cstamp, ifmca->mca_tstamp,
                          INFINITY_LIFE_TIME, INFINITY_LIFE_TIME) < 0) {
                nlmsg_cancel(skb, nlh);
                return -EMSGSIZE;
        }

        return nlmsg_end(skb, nlh);
}

static int inet6_fill_ifacaddr(struct sk_buff *skb, struct ifacaddr6 *ifaca,
                                u32 portid, u32 seq, int event, unsigned int flags)
{
        struct nlmsghdr  *nlh;
        u8 scope = RT_SCOPE_UNIVERSE;
        int ifindex = ifaca->aca_idev->dev->ifindex;

        if (ipv6_addr_scope(&ifaca->aca_addr) & IFA_SITE)
                scope = RT_SCOPE_SITE;

        nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct ifaddrmsg), flags);
        if (nlh == NULL)
                return -EMSGSIZE;

        put_ifaddrmsg(nlh, 128, IFA_F_PERMANENT, scope, ifindex);
        if (nla_put(skb, IFA_ANYCAST, 16, &ifaca->aca_addr) < 0 ||
            put_cacheinfo(skb, ifaca->aca_cstamp, ifaca->aca_tstamp,
                          INFINITY_LIFE_TIME, INFINITY_LIFE_TIME) < 0) {
                nlmsg_cancel(skb, nlh);
                return -EMSGSIZE;
        }

        return nlmsg_end(skb, nlh);
}

enum addr_type_t {
        UNICAST_ADDR,
        MULTICAST_ADDR,
        ANYCAST_ADDR,
};

/* called with rcu_read_lock() */
static int in6_dump_addrs(struct inet6_dev *idev, struct sk_buff *skb,
                          struct netlink_callback *cb, enum addr_type_t type,
                          int s_ip_idx, int *p_ip_idx)
{
        struct ifmcaddr6 *ifmca;
        struct ifacaddr6 *ifaca;
        int err = 1;
        int ip_idx = *p_ip_idx;

        read_lock_bh(&idev->lock);
        switch (type) {
        case UNICAST_ADDR: {
                struct inet6_ifaddr *ifa;

                /* unicast address incl. temp addr */
                list_for_each_entry(ifa, &idev->addr_list, if_list) {
                        if (++ip_idx < s_ip_idx)
                                continue;
                        err = inet6_fill_ifaddr(skb, ifa,
                                                NETLINK_CB(cb->skb).portid,
                                                cb->nlh->nlmsg_seq,
                                                RTM_NEWADDR,
                                                NLM_F_MULTI);
                        if (err <= 0)
                                break;
                        nl_dump_check_consistent(cb, nlmsg_hdr(skb));
                }
                break;
        }
        case MULTICAST_ADDR:
                /* multicast address */
                for (ifmca = idev->mc_list; ifmca;
                     ifmca = ifmca->next, ip_idx++) {
                        if (ip_idx < s_ip_idx)
                                continue;
                        err = inet6_fill_ifmcaddr(skb, ifmca,
                                                  NETLINK_CB(cb->skb).portid,
                                                  cb->nlh->nlmsg_seq,
                                                  RTM_GETMULTICAST,
                                                  NLM_F_MULTI);
                        if (err <= 0)
                                break;
                }
                break;
        case ANYCAST_ADDR:
                /* anycast address */
                for (ifaca = idev->ac_list; ifaca;
                     ifaca = ifaca->aca_next, ip_idx++) {
                        if (ip_idx < s_ip_idx)
                                continue;
                        err = inet6_fill_ifacaddr(skb, ifaca,
                                                  NETLINK_CB(cb->skb).portid,
                                                  cb->nlh->nlmsg_seq,
                                                  RTM_GETANYCAST,
                                                  NLM_F_MULTI);
                        if (err <= 0)
                                break;
                }
                break;
        default:
                break;
        }
        read_unlock_bh(&idev->lock);
        *p_ip_idx = ip_idx;
        return err;
}

static int inet6_dump_addr(struct sk_buff *skb, struct netlink_callback *cb,
                           enum addr_type_t type)
{
        struct net *net = sock_net(skb->sk);
        int h, s_h;
        int idx, ip_idx;
        int s_idx, s_ip_idx;
        struct net_device *dev;
        struct inet6_dev *idev;
        struct hlist_head *head;

        s_h = cb->args[0];
        s_idx = idx = cb->args[1];
        s_ip_idx = ip_idx = cb->args[2];

        rcu_read_lock();
        cb->seq = atomic_read(&net->ipv6.dev_addr_genid) ^ net->dev_base_seq;
        for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
                idx = 0;
                head = &net->dev_index_head[h];